octeontx2-af: Fix a resource leak in an error handling path in 'cgx_probe()'

If an error occurs after the call to 'pci_alloc_irq_vectors()', we must
call 'pci_free_irq_vectors()' in order to avoid a	resource leak.

The same sequence is already in place in the corresponding 'cgx_remove()'
function.

Fixes: 1463f382

 ("octeontx2-af: Add support for CGX link management")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>