s390/maccess: remove dead DAT-off code

As the kernel is executed in DAT-on mode only, remove
unnecessary DAT bit check together with the dead code.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/mm/maccess.c

@@ -68,15 +68,11 @@ notrace void *s390_kernel_write(void *dst, const void *src, size_t size)
 	long copied;
 
 	spin_lock_irqsave(&s390_kernel_write_lock, flags);
-	if (!(flags & PSW_MASK_DAT)) {
-		memcpy(dst, src, size);
-	} else {
-		while (size) {
-			copied = s390_kernel_write_odd(tmp, src, size);
-			tmp += copied;
-			src += copied;
-			size -= copied;
-		}
+	while (size) {
+		copied = s390_kernel_write_odd(tmp, src, size);
+		tmp += copied;
+		src += copied;
+		size -= copied;
 	}
 	spin_unlock_irqrestore(&s390_kernel_write_lock, flags);