RDMA/cxgb4: Fix underflows in c4iw_create_qp()

These sizes should be unsigned so we don't allow negative values and
have underflow bugs.  These can come from the user so there may be
security implications, but I have not tested this.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/cxgb4/qp.c

@@ -1533,7 +1533,7 @@ struct ib_qp *c4iw_create_qp(struct ib_pd *pd, struct ib_qp_init_attr *attrs,
 	struct c4iw_cq *schp;
 	struct c4iw_cq *rchp;
 	struct c4iw_create_qp_resp uresp;
-	int sqsize, rqsize;
+	unsigned int sqsize, rqsize;
 	struct c4iw_ucontext *ucontext;
 	int ret;
 	struct c4iw_mm_entry *mm1, *mm2, *mm3, *mm4, *mm5 = NULL;