De-constify sched.h

[PATCH] De-constify sched.h

This reverts commit a8972ccf00b7184a743eb6cd9bc7f3443357910c ("sched:
constify sched.h")

 1) Patch doesn't change any code here, so gcc is already smart enough
    to "feel" constness in such simple functions.
 2) There is no such thing as const task_struct.  Anyone who think
    otherwise deserves compiler warning.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --cc include/linux/sched.h
Simple merge