watchdog: diag288_wdt: fix __diag288() inline assembly

The DIAG 288 statement consumes an EBCDIC string the address of which is
passed in a register. Use a "memory" clobber to tell the compiler that
memory is accessed within the inline assembly.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

drivers/watchdog/diag288_wdt.c

@@ -86,7 +86,7 @@ static int __diag288(unsigned int func, unsigned int timeout,
 		"1:\n"
 		EX_TABLE(0b, 1b)
 		: "+d" (err) : "d"(__func), "d"(__timeout),
-		  "d"(__action), "d"(__len) : "1", "cc");
+		  "d"(__action), "d"(__len) : "1", "cc", "memory");
 	return err;
 }