drivers:net: Remove unnecessary OOM messages after netdev_alloc_skb

Emitting netdev_alloc_skb and netdev_alloc_skb_ip_align OOM
messages is unnecessary as there is already a dump_stack
after allocation failures.

Other trivial changes around these removals:

Convert a few comparisons of pointer to 0 to !pointer.
Change flow to remove unnecessary label.
Remove now unused variable.
Hoist assignment from if.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index d6cb376..eec0af4 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -245,10 +245,8 @@
 
 	/* Alloc skb */
 	slot->skb = netdev_alloc_skb(bgmac->net_dev, BGMAC_RX_BUF_SIZE);
-	if (!slot->skb) {
-		bgmac_err(bgmac, "Allocation of skb failed!\n");
+	if (!slot->skb)
 		return -ENOMEM;
-	}
 
 	/* Poison - if everything goes fine, hardware will overwrite it */
 	rx = (struct bgmac_rx_header *)slot->skb->data;