hrtimer: Remove redundant #ifdef block

Only need CONFIG_NO_HZ_COMMON as this block is already in a
CONFIG_SMP block.

Signed-off-by: Pratyush Patel <pratyushpatel.1995@gmail.com>
Link: http://lkml.kernel.org/r/20160301172849.GA18152@cyborg


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>