sb/intel/common/rcba.h: Guard RCBAx macro parameters

Add brackets around the parameters to avoid operation order problems.

Change-Id: I689983b5b937f66b1a520eea61a38fb96c13c007
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50035
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/southbridge/intel/common/rcba.h b/src/southbridge/intel/common/rcba.h
index 51c4046..712a477 100644
--- a/src/southbridge/intel/common/rcba.h
+++ b/src/southbridge/intel/common/rcba.h
@@ -11,10 +11,10 @@
 #define RCBA 0xf0
 #define RCBA_ENABLE 0x01
 
-#define RCBA8(x) (*((volatile u8 *)(DEFAULT_RCBA + x)))
-#define RCBA16(x) (*((volatile u16 *)(DEFAULT_RCBA + x)))
-#define RCBA32(x) (*((volatile u32 *)(DEFAULT_RCBA + x)))
-#define RCBA64(x) (*((volatile u64 *)(DEFAULT_RCBA + x)))
+#define RCBA8(x)  (*((volatile u8  *)(DEFAULT_RCBA + (x))))
+#define RCBA16(x) (*((volatile u16 *)(DEFAULT_RCBA + (x))))
+#define RCBA32(x) (*((volatile u32 *)(DEFAULT_RCBA + (x))))
+#define RCBA64(x) (*((volatile u64 *)(DEFAULT_RCBA + (x))))
 
 #define RCBA_AND_OR(bits, x, and, or) \
 	(RCBA##bits(x) = ((RCBA##bits(x) & (and)) | (or)))