net/macb: unify peripheral version testing

As we need to check peripheral version from the hardware during probe, I
introduce a little helper to unify these tests. It would prevent to
de-synchronize the test like previously observed.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 4412895..448a323 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -2139,10 +2139,9 @@
 	if (dt_conf)
 		bp->caps = dt_conf->caps;
 
-	if (MACB_BFEXT(IDNUM, macb_readl(bp, MID)) >= 0x2)
+	if (macb_is_gem_hw(bp->regs)) {
 		bp->caps |= MACB_CAPS_MACB_IS_GEM;
 
-	if (macb_is_gem(bp)) {
 		dcfg = gem_readl(bp, DCFG1);
 		if (GEM_BFEXT(IRQCOR, dcfg) == 0)
 			bp->caps |= MACB_CAPS_ISR_CLEAR_ON_WRITE;
@@ -2159,7 +2158,6 @@
 			      unsigned int *num_queues)
 {
 	unsigned int hw_q;
-	u32 mid;
 
 	*queue_mask = 0x1;
 	*num_queues = 1;
@@ -2170,8 +2168,7 @@
 	 * we are early in the probe process and don't have the
 	 * MACB_CAPS_MACB_IS_GEM flag positioned
 	 */
-	mid = readl_relaxed(mem + MACB_MID);
-	if (MACB_BFEXT(IDNUM, mid) < 0x2)
+	if (!macb_is_gem_hw(mem))
 		return;
 
 	/* bit 0 is never set but queue 0 always exists */