[PATCH] IB/mthca: Factor out common queue alloc code

Clean up the allocation of memory for queues by factoring out the
common code into mthca_buf_alloc() and mthca_buf_free().  Now CQs and
QPs share the same queue allocation code, which we'll also use for SRQs.

Signed-off-by: Roland Dreier <rolandd@cisco.com>