IB/mlx4: Fix gfp passing in create_qp_common()

There are two kzalloc() calls which were not converted to use value of
gfp passed to create_qp_common() instead of using hardcoded GFP_KERNEL
in 40f2287b ("IB/mlx4: Implement IB_QP_CREATE_USE_GFP_NOIO").  Fix
this by passing gfp value down properly.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Roland Dreier <roland@purestorage.com>