net: ti: Use FIELD_SIZEOF directly instead of reimplementing its function

FIELD_SIZEOF is defined as a macro to calculate the specified value. Therefore,
We prefer to use the macro rather than calculating its value.
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpsw.c

@@ -484,13 +484,13 @@ enum {
 };
 
 #define CPSW_STAT(m)		CPSW_STATS,				\
-				sizeof(((struct cpsw_hw_stats *)0)->m), \
+				FIELD_SIZEOF(struct cpsw_hw_stats, m), \
 				offsetof(struct cpsw_hw_stats, m)
 #define CPDMA_RX_STAT(m)	CPDMA_RX_STATS,				   \
-				sizeof(((struct cpdma_chan_stats *)0)->m), \
+				FIELD_SIZEOF(struct cpdma_chan_stats, m), \
 				offsetof(struct cpdma_chan_stats, m)
 #define CPDMA_TX_STAT(m)	CPDMA_TX_STATS,				   \
-				sizeof(((struct cpdma_chan_stats *)0)->m), \
+				FIELD_SIZEOF(struct cpdma_chan_stats, m), \
 				offsetof(struct cpdma_chan_stats, m)
 
 static const struct cpsw_stats cpsw_gstrings_stats[] = {