Move functions to setup msi from xhci.c to xhci-pci.c to decouple
PCI specific code from generic xhci code.

No functional changes, functions are an exact copy

[commit message rewording -Mathias]
Signed-off-by: Josue David Hernandez Gutierrez <josue.d.hernandez.gutierrez@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20230317154715.535523-11-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>