[S390] fix s390x_newuname

The uname system call for 64 bit compares current->personality without
masking the upper 16 bits. If e.g. READ_IMPLIES_EXEC is set the result
of a uname system call will always be s390x even if the process uses
the s390 personality.

Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/kernel/sys_s390.c

···
 {
 	int ret = sys_newuname(name);
 
-	if (current->personality == PER_LINUX32 && !ret) {
+	if (personality(current->personality) == PER_LINUX32 && !ret) {
 		ret = copy_to_user(name->machine, "s390\0\0\0\0", 8);
 		if (ret) ret = -EFAULT;
 	}