timers: Fix kernel-doc format and add Return values
Fix kernel-doc format and warnings:
timer.h:26: warning: Cannot understand * @TIMER_DEFERRABLE: A deferrable timer will work normally when the on line 26 - I thought it was a doc line
timer.h:146: warning: No description found for return value of 'timer_pending'
timer.h:180: warning: No description found for return value of 'del_timer_sync'
timer.h:193: warning: No description found for return value of 'del_timer'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240331172652.14086-4-rdunlap@infradead.org