workqueue: remove redundant function invocation

timer_stats_timer_set_start_info is invoked twice, additionally, the
invocation of this function can be moved to where it is only called when a
delay is really required.

Signed-off-by: Andrew Liu <shengping.liu@windriver.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>