8139cp: Fix skb leak in rx_status_loop failure path.

[ Upstream commit d06f5187469eee1b2932c02fd093d113cfc60d5e ]

Introduced in cf3c4c03060b688cbc389ebc5065ebcce5653e96
("8139cp: Add dma_mapping_error checking")

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>