hrtimer: remove unneeded kallsyms include

hrtimer does not seem to use any of kallsyms functions/defines.

Link: http://lkml.kernel.org/r/20171208025616.16267-9-sergey.senozhatsky@gmail.com


Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>