RDMA/mad: Convert BUG_ONs to error flows

Let's perform checks in-place instead of BUG_ONs.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/mad.c

@@ -1556,7 +1556,8 @@ static int add_oui_reg_req(struct ib_mad_reg_req *mad_reg_req,
 			    mad_reg_req->oui, 3)) {
 			method = &(*vendor_table)->vendor_class[
 						vclass]->method_table[i];
-			BUG_ON(!*method);
+			if (!*method)
+				goto error3;
 			goto check_in_use;
 		}
 	}
@@ -1566,10 +1567,12 @@ static int add_oui_reg_req(struct ib_mad_reg_req *mad_reg_req,
 				vclass]->oui[i])) {
 			method = &(*vendor_table)->vendor_class[
 				vclass]->method_table[i];
-			BUG_ON(*method);
 			/* Allocate method table for this OUI */
-			if ((ret = allocate_method_table(method)))
+			if (!*method) {
+				ret = allocate_method_table(method);
+				if (ret)
 					goto error3;
+			}
 			memcpy((*vendor_table)->vendor_class[vclass]->oui[i],
 			       mad_reg_req->oui, 3);
 			goto check_in_use;