[PATCH] Add const for time{spec,val}_compare arguments

The arguments are really const.  Mark them const to allow these functions
being called from places where the arguments are const without getting
useless compiler warnings.

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>