serial: cpm_uart: Remove stale prototypes and table and macros

serial: cpm_uart: Remove stale prototypes and table and macros

cpm_uart_init_portdesc()
smc1_lineif()
smc2_lineif()
scc1_lineif()
scc2_lineif()
scc3_lineif()
scc4_lineif()

Those functions were removed by commit 0b2a2e5b7747 ("cpm_uart: Remove
!CONFIG_PPC_CPM_NEW_BINDING code"). Remove stale prototypes.

UART_SMC{1..2} and UART_SCC{1..4} and SCC_WAIT_CLOSING macros are not
used anymore since the above commit.

cpm_uart_ports[] isn't used outside cpm_uart_core.c since the
same commit, so make it static.

cpm_uart_init_smc() and cpm_uart_init_scc() don't need a forward
declaration.

FLAG_DISCARDING and IS_DISCARDING have never been used since at
least 2.6.12 and the start of git repository for kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/96ef20ae1df056d1b7967871ba6e27e5b5aaeea6.1691068700.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>