misc: ti-st: st_core: Tidy-up bespoke commentry

misc: ti-st: st_core: Tidy-up bespoke commentry

If it's still in use and worth the effort, it sure looks like
this driver could do with a good scrub (clean).

This patch conserns itself with the non-standard comments located
thoughout the file.

It also fixes the following W=1 warnings by demoting the kerneldoc
function headers to standard comments, since there doesn't appear
to be a requirement for the function args to be documented:

 drivers/misc/ti-st/st_core.c:132: warning: Function parameter or member 'st_gdata' not described in 'st_reg_complete'
 drivers/misc/ti-st/st_core.c:132: warning: Function parameter or member 'err' not described in 'st_reg_complete'
 drivers/misc/ti-st/st_core.c:197: warning: Function parameter or member 'st_gdata' not described in 'st_wakeup_ack'
 drivers/misc/ti-st/st_core.c:197: warning: Function parameter or member 'cmd' not described in 'st_wakeup_ack'
 drivers/misc/ti-st/st_core.c:226: warning: Function parameter or member 'disc_data' not described in 'st_int_recv'
 drivers/misc/ti-st/st_core.c:226: warning: Function parameter or member 'data' not described in 'st_int_recv'
 drivers/misc/ti-st/st_core.c:226: warning: Function parameter or member 'count' not described in 'st_int_recv'
 drivers/misc/ti-st/st_core.c:387: warning: Function parameter or member 'st_gdata' not described in 'st_int_dequeue'
 drivers/misc/ti-st/st_core.c:409: warning: Function parameter or member 'st_gdata' not described in 'st_int_enqueue'
 drivers/misc/ti-st/st_core.c:409: warning: Function parameter or member 'skb' not described in 'st_int_enqueue'

Cc: Pavan Savoy <pavan_savoy@ti.com>
Cc: Naveen Jain <naveen_jain@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200626130525.389469-3-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>