bnxt_en: Fix TX push operation on ARM64.

There is a code path where we are calling __iowrite64_copy() on
an address that is not 64-bit aligned.  This causes an exception on
some architectures such as arm64.  Fix that code path by using
__iowrite32_copy().
Reported-by: JD Zheng <jiandong.zheng@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -353,8 +353,8 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		push_len = (length + sizeof(*tx_push) + 7) / 8;
 		if (push_len > 16) {
 			__iowrite64_copy(txr->tx_doorbell, tx_push_buf, 16);
-			__iowrite64_copy(txr->tx_doorbell + 4, tx_push_buf + 1,
-					 push_len - 16);
+			__iowrite32_copy(txr->tx_doorbell + 4, tx_push_buf + 1,
+					 (push_len - 16) << 1);
 		} else {
 			__iowrite64_copy(txr->tx_doorbell, tx_push_buf,
 					 push_len);