net: ethernet: nixge: fix NULL dereference

net: ethernet: nixge: fix NULL dereference

[ Upstream commit 792b54b999acb8ad37c5afb09d8f35f1d61287e3 ]

In function nixge_hw_dma_bd_release() dereference of NULL pointer
priv->rx_bd_v is possible for the case of its allocation failure in
nixge_hw_dma_bd_init().

Move for() loop with priv->rx_bd_v dereference under the check for
its validity.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 6ac9dc63fb5b ("net: ethernet: nixge: Add support for National Instruments XGE netdev")
Signed-off-by: Yuri Karpov <YKarpov@ispras.ru>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>