pci: rework interrupt fd init and fix fd leak

pci: rework interrupt fd init and fix fd leak

A fd leak happens in pci_map_resource when multiple bars are mapped.
Fix this by closing fd unconditionnally in this function and open the
intr_handle fd in pci_uio_map_resource instead.

Signed-off-by: David Marchand <david.marchand@6wind.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>