Revert "prctl: adds the capable(CAP_SYS_NICE) check to PR_SET_TIMERSLACK_PID."

This reverts commit 76f2236f76f6b69d32310b2504c743603f9ffc85.
Revert "prctl: adds PR_SET_TIMERSLACK_PID for setting timer slack of an arbitrary thread."

This reverts commit 560dcb37dc56d9a233c5f4fd831f1c7761204c19.
Revert "Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs"

This reverts commit 612fea6b25b3e16a8d9a81aa477e7779819b9994.

Conflicts:
	include/linux/prctl.h
	kernel/sys.c

Revert "Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting…
… privs"
*Also fix merge conflicts