vfio: fix maximum number of interrupt for MSI-X
vfio: fix maximum number of interrupt for MSI-X

The max number of interrupt request is possible
be changed after rte_intr_callback_register, so
in get_max_intr, we need to check if necessary to
update the max_intr.

Signed-off-by: Qi Zhang <9e9e58ffa71a29bb7b87766b362515be648fcbe0@intel.com>

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