ethdev: decouple interrupt handling from PCI device

The struct rte_intr_handle is an abstraction layer for different types of
interrupt mechanisms. It is embedded in the low-level device (e.g. PCI).
On allocation of a struct rte_eth_dev a reference to the intr_handle
should be stored for devices supporting interrupts.

Signed-off-by: Jan Blunck <jblunck@infradead.org>
Acked-by: Shreyansh Jain <shreyansh.jain@nxp.com>