s390: add missing "do {} while (0)" loop constructs to multiline macros

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/processor.h

@@ -358,12 +358,12 @@ extern void (*s390_base_ext_handler_fn)(void);
 extern int memcpy_real(void *, void *, size_t);
 extern void memcpy_absolute(void *, void *, size_t);
 
-#define mem_assign_absolute(dest, val) {			\
+#define mem_assign_absolute(dest, val) do {			\
 	__typeof__(dest) __tmp = (val);				\
 								\
 	BUILD_BUG_ON(sizeof(__tmp) != sizeof(val));		\
 	memcpy_absolute(&(dest), &__tmp, sizeof(__tmp));	\
-}
+} while (0)
 
 #endif /* __ASSEMBLY__ */