[SCSI] megaraid: Use resource_size_t for PCI resources, not long

The assumption that sizeof(long) >= sizeof(resource_size_t) can lead to
truncation of the PCI resource address, meaning this driver didn't work
on 32-bit systems with 64-bit PCI adressing ranges.

Signed-off-by: Ben Collins <ben.c@servergy.com>
Acked-by: Sumit Saxena <sumit.saxena@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>