stmmac: don't return zero on failure path in stmmac_pci_probe()

If stmmac_dvr_probe() fails in stmmac_pci_probe(), it breaks off initialization,
deallocates all resources, but returns zero.
The patch adds -ENODEV as return value in this case.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>