[SCSI] bfa: use pci_iomap() and pci_iounmap()

Use pci_iomap() and pci_iounmap() to simplify the code. Remove uncessary #ifdef
check for ia64 (it was added as a workaound for some RHEL 5.x release which
doesn't export iounmap function)

Signed-off-by: Jing Huang <huangj@brocade.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>