net: mvgbe: extract common code for SMI wait

Combine repeated code from smi_reg_read/smi_reg_write into a common
function smi_wait_ready.

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Chris Packham <judge.packham@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/mvgbe.h b/drivers/net/mvgbe.h
index c20d1d7..1dc9bbe 100644
--- a/drivers/net/mvgbe.h
+++ b/drivers/net/mvgbe.h
@@ -216,6 +216,7 @@
 
 /* SMI register fields */
 #define MVGBE_PHY_SMI_TIMEOUT		10000
+#define MVGBE_PHY_SMI_TIMEOUT_MS	1000
 #define MVGBE_PHY_SMI_DATA_OFFS		0	/* Data */
 #define MVGBE_PHY_SMI_DATA_MASK		(0xffff << MVGBE_PHY_SMI_DATA_OFFS)
 #define MVGBE_PHY_SMI_DEV_ADDR_OFFS	16	/* PHY device address */