x86_64: Calgary - change _map_single, etc to static

there function are called via dma_ops->.., so change them to static

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>