net: mvpp2: fix MVPP21_ISR_RXQ_GROUP_REG definition

The MVPP21_ISR_RXQ_GROUP_REG register is not indexed by rxq, but by
port, so we fix the parameter name accordingly. There are no
functional changes.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2.c

@@ -185,7 +185,7 @@
 /* Interrupt Cause and Mask registers */
 #define MVPP2_ISR_RX_THRESHOLD_REG(rxq)		(0x5200 + 4 * (rxq))
 #define     MVPP2_MAX_ISR_RX_THRESHOLD		0xfffff0
-#define MVPP21_ISR_RXQ_GROUP_REG(rxq)		(0x5400 + 4 * (rxq))
+#define MVPP21_ISR_RXQ_GROUP_REG(port)		(0x5400 + 4 * (port))
 
 #define MVPP22_ISR_RXQ_GROUP_INDEX_REG          0x5400
 #define MVPP22_ISR_RXQ_GROUP_INDEX_SUBGROUP_MASK 0xf