Input: omap4-keypad - react on keypresses if device is runtime-suspended

Input: omap4-keypad - react on keypresses if device is runtime-suspended

According to SWPU235AB, table 26-6, fclk is required to generate events
at least on OMAP4460, so keep fclk enabled all the time the device
is opened.

Suggested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20231211221757.517427-1-andreas@kemnade.info
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>