enetc: Add missing call to 'pci_free_irq_vectors()' in probe and remove functions

Call to 'pci_free_irq_vectors()' are missing both in the error handling
path of the probe function, and in the remove function.
Add them.

Fixes: 19971f5e

 ("enetc: add PTP clock driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>