ia64, sched/cputime: Fix build error if CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y

ia64, sched/cputime: Fix build error if CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y

Remove the extra parenthesis.

This bug was introduced by:

  e2339a4caa5e: ("ia64: Convert vtime to use nsec units directly")

Signed-off-by: Valentin Ilie <valentin.ilie@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: linux-ia64@vger.kernel.org
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/1515193979-24873-1-git-send-email-valentin.ilie@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>