staging: most: dim2: Provide missing descriptions and fix doc-rot

staging: most: dim2: Provide missing descriptions and fix doc-rot

Also demote merely half-complete header.

Fixes the following W=1 kernel build warning(s):

 drivers/staging/most/dim2/dim2.c:69: warning: Function parameter or member 'name' not described in 'hdm_channel'
 drivers/staging/most/dim2/dim2.c:69: warning: Function parameter or member 'reset_dbr_size' not described in 'hdm_channel'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'dev' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'name' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'clk_speed' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'clk' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'clk_pll' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'bus' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'on_netinfo' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:104: warning: Function parameter or member 'disable_platform' not described in 'dim2_hdm'
 drivers/staging/most/dim2/dim2.c:440: warning: Function parameter or member 'most_iface' not described in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:440: warning: Function parameter or member 'ch_idx' not described in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:440: warning: Function parameter or member 'ccfg' not described in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:440: warning: Excess function parameter 'iface' description in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:440: warning: Excess function parameter 'channel' description in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:440: warning: Excess function parameter 'channel_config' description in 'configure_channel'
 drivers/staging/most/dim2/dim2.c:558: warning: Function parameter or member 'most_iface' not described in 'enqueue'
 drivers/staging/most/dim2/dim2.c:558: warning: Function parameter or member 'ch_idx' not described in 'enqueue'
 drivers/staging/most/dim2/dim2.c:558: warning: Excess function parameter 'iface' description in 'enqueue'
 drivers/staging/most/dim2/dim2.c:558: warning: Excess function parameter 'channel' description in 'enqueue'
 drivers/staging/most/dim2/dim2.c:591: warning: Function parameter or member 'most_iface' not described in 'request_netinfo'
 drivers/staging/most/dim2/dim2.c:591: warning: Function parameter or member 'ch_idx' not described in 'request_netinfo'
 drivers/staging/most/dim2/dim2.c:591: warning: Function parameter or member 'on_netinfo' not described in 'request_netinfo'
 drivers/staging/most/dim2/dim2.c:591: warning: Excess function parameter 'iface' description in 'request_netinfo'
 drivers/staging/most/dim2/dim2.c:591: warning: Excess function parameter 'channel_id' description in 'request_netinfo'
 drivers/staging/most/dim2/dim2.c:631: warning: Function parameter or member 'most_iface' not described in 'poison_channel'
 drivers/staging/most/dim2/dim2.c:631: warning: Function parameter or member 'ch_idx' not described in 'poison_channel'
 drivers/staging/most/dim2/dim2.c:631: warning: Excess function parameter 'iface' description in 'poison_channel'
 drivers/staging/most/dim2/dim2.c:631: warning: Excess function parameter 'channel_id' description in 'poison_channel'

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nícolas F. R. A. Prado" <nfraprado@protonmail.com>
Cc: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Cc: linux-staging@lists.linux.dev
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210414181129.1628598-30-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>