s390/process: fix sfpc inline assembly

commit e47994dd upstream.

The sfpc inline assembly within execve_tail() may incorrectly set bits
28-31 of the sfpc instruction to a value which is not zero.
These bits however are currently unused and therefore should be zero
so we won't get surprised if these bits will be used in the future.

Therefore remove the second operand from the inline assembly.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>

arch/s390/kernel/process.c

@@ -246,7 +246,7 @@ asmlinkage void execve_tail(void)
 {
 	current->thread.fp_regs.fpc = 0;
 	if (MACHINE_HAS_IEEE)
-		asm volatile("sfpc %0,%0" : : "d" (0));
+		asm volatile("sfpc %0" : : "d" (0));
 }
 
 /*