pci: initialize generic driver pointer

The existing code initializes a PCI driver pointer but not the common one.
As the result, ring_dma_zone_reserve() in drivers/net/bnx2x/bnx2x_rxtx.c
crashed as dev->device->driver==NULL.

This adds missing initialization.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

lib/librte_eal/common/eal_common_pci.c

@@ -244,6 +244,7 @@ rte_eal_pci_probe_one_driver(struct rte_pci_driver *dr,
 
 	/* reference driver structure */
 	dev->driver = dr;
+	dev->device.driver = &dr->driver;
 
 	/* call the driver probe() function */
 	ret = dr->probe(dr, dev);