Fix move msix_vector_use() to device reset

Originally, the msix_vector_use() setup was done as a part of device
initialization (pci_nvme_init). But the device reset now calls
msix_reset() which in turn calls msix_free_irq_entries() which resets
all the "vector used" values to zero.

Move the msix_vector_use() call to after the MSI-X reset to re-allow
MSI-X interrupts after a reset e.g. cold for start of day as well as
Function Level.

Signed-off-by: Chuck Tuffli <chuck.tuffli@oakgatetech.com>