MSI: Combine pci_(save|restore)_msi/msix_state

The PCI save/restore code doesn't need to care about MSI vs MSI-X, all
it really wants is to say "save/restore all MSI(-X) info for this device".

This is borne out in the code, we call the MSI and MSI-X save routines
side by side, and similarly with the restore routines.

So combine the MSI/MSI-X routines into pci_save_msi_state() and
pci_restore_msi_state(). It is up to those routines to decide what state
needs to be saved.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>