In hitherto code in case of RX buffer allocation error during refill,
original buffer is pushed to the network stack, but the amount of
available buffer pointers in BM pool is decreased.

This commit fixes the situation by moving refill call before skb_put(),
and returning original buffer pointer to the pool in case of an error.
Signed-off-by: Marcin Wojtas <mw@semihalf.com>

Fixes: 3f518509 ("ethernet: Add new driver for Marvell Armada 375
network unit")

Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: David S. Miller <davem@davemloft.net>