[S390] no execute support cleanup.

From: Martin Schwidefsky <[EMAIL PROTECTED]> [S390] no execute support cleanup. Simplify the signal_return function that checks for the two special system calls sigreturn and rt_sigreturn. No need to do a page table walk, a call to copy_from_user while disabled page faults will work a

[S390] no execute support cleanup.

From: Martin Schwidefsky [EMAIL PROTECTED] [S390] no execute support cleanup. Simplify the signal_return function that checks for the two special system calls sigreturn and rt_sigreturn. No need to do a page table walk, a call to copy_from_user while disabled page faults will work as well