Add support for allocating user access regions (UARs).  Use this to
allocate a region for kernel at driver init instead using hard-coded
MTHCA_KAR_PAGE index.
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>