net/nfp: fix Rx interrupt when multiqueue
net/nfp: fix Rx interrupt when multiqueue

intr_vec was not properly configured. This is not a problem when
just one queue is supported but it fails with multiqueue.

Some minor refactoring also done for hardware interrupt configuration.

Fixes: ea121b28316d ("net/nfp: add Rx interrupts")
Cc: stable@dpdk.org

Signed-off-by: Alejandro Lucero <1ffca3a1926aae782ae3c39a5b308878ba1e5683@netronome.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk