[SPARC64]: Fix pci_intmap_match().

When crawling up the PCI bus chain, stop at the first node
that has an interrupt-map property before we hit the root.

Also, if we use a bus interrupt-{map,mask} do not forget to
update the 'intmask' pointer as we do for the 'intmap' pointer.

Signed-off-by: David S. Miller <davem@davemloft.net>