vtime, sched/cputime: Remove vtime_account_user()

vtime, sched/cputime: Remove vtime_account_user()

It's an unnecessary function between vtime_user_exit() and
account_user_time().

Tested-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1498756511-11714-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>