Use ERR_CAST inlined function instead of ERR_PTR(PTR_ERR(...)).
net/bridge/br_multicast.c:1246:9-16: WARNING: ERR_CAST can be used with mp
Generated by: scripts/coccinelle/api/err_cast.cocci
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20210204070549.83636-1-vulab@iscas.ac.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 
        mp = br_multicast_new_group(br, group);
        if (IS_ERR(mp))
-               return ERR_PTR(PTR_ERR(mp));
+               return ERR_CAST(mp);
 
        if (!port) {
                br_multicast_host_join(mp, true);