[PATCH] IB/mthca: encapsulate mem-free check into mthca_is_memfree()

Clean up mem-free mode support by introducing mthca_is_memfree() function,
which encapsulates the logic of deciding if a device is mem-free.

Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>