mlxsw: spectrum_router: Fix error handling issue

Return error to the caller instead of suppressing it.

Fixes: e3ddfb45 ("mlxsw: spectrum_router: Allow returning errors from mlxsw_sp_nexthop_group_refresh()")
Addresses-Coverity: ("Error handling issues  (CHECKED_RETURN)")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -3608,10 +3608,8 @@ mlxsw_sp_nexthop_group_refresh(struct mlxsw_sp *mlxsw_sp,
 	int i, err2, err = 0;
 	u32 old_adj_index;
 
-	if (!nhgi->gateway) {
-		mlxsw_sp_nexthop_fib_entries_update(mlxsw_sp, nh_grp);
-		return 0;
-	}
+	if (!nhgi->gateway)
+		return mlxsw_sp_nexthop_fib_entries_update(mlxsw_sp, nh_grp);
 
 	for (i = 0; i < nhgi->count; i++) {
 		nh = &nhgi->nexthops[i];