Convert pa_dev->hpa from an unsigned long to a struct resource.
Signed-off-by: NMatthew Wilcox <willy@parisc-linux.org>

Fix up users of ->hpa to use ->hpa.start instead.
Signed-off-by: NMatthew Wilcox <willy@parisc-linux.org>
Signed-off-by: NKyle McMartin <kyle@parisc-linux.org>