[PATCH] IB: Fix FMR pool crash

Mask bits correctly from jhash result in ib_fmr_hash() so that the
computed bucket index is within our hash table.  This fixes an SDP
crash.

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