GenWQE: Use pci_enable_msi_exact() instead of pci_enable_msi_block()

As result of deprecation of MSI-X/MSI enablement functions
pci_enable_msix() and pci_enable_msi_block() all drivers using these two
interfaces need to be updated to use the new pci_enable_msi_range()  or
pci_enable_msi_exact() and pci_enable_msix_range() or
pci_enable_msix_exact() interfaces.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>