qlcnic: Fix a memory leak in error handling path

If 'dma_alloc_coherent()' fails, we should release resources allocated so
far, just as done in all other cases in this function.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>