sched: fix init_hrtick() section mismatch warning

LD      kernel/built-in.o
WARNING: kernel/built-in.o(.text+0x326): Section mismatch in reference
from the function init_hrtick() to the variable
.cpuinit.data:hotplug_hrtick_nb.8
The function init_hrtick() references
the variable __cpuinitdata hotplug_hrtick_nb.8.
This is often because init_hrtick lacks a __cpuinitdata
annotation or the annotation of hotplug_hrtick_nb.8 is wrong.

Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>