net: bridge: multicast: fix br_multicast_eht_set_entry_lookup indentation

Fix the messed up indentation in br_multicast_eht_set_entry_lookup().

Fixes: baa74d39

 ("net: bridge: multicast: add EHT source set handling functions")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20210125082040.13022-1-razor@blackwall.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>