net: dsa: mt7530: fix macro MIRROR_PORT

The inner pair of parentheses should be around the variable x

Fixes: 37feab60 ("net: dsa: mt7530: add support for port mirroring")
Signed-off-by: DENG Qingfang <dqfext@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mt7530.h

@@ -37,7 +37,7 @@ enum {
 #define  CPU_PORT(x)			((x) << 4)
 #define  CPU_MASK			(0xf << 4)
 #define  MIRROR_EN			BIT(3)
-#define  MIRROR_PORT(x)			((x & 0x7))
+#define  MIRROR_PORT(x)			((x) & 0x7)
 #define  MIRROR_MASK			0x7
 
 /* Registers for address table access */