mlxsw: spectrum_mr: Fix list iteration in error path

mlxsw: spectrum_mr: Fix list iteration in error path

BugLink: https://bugs.launchpad.net/bugs/1870604
[ Upstream commit f6bf1bafdc2152bb22aff3a4e947f2441a1d49e2 ]

list_for_each_entry_from_reverse() iterates backwards over the list from
the current position, but in the error path we should start from the
previous position.

Fix this by using list_for_each_entry_continue_reverse() instead.

This suppresses the following error from coccinelle:

drivers/net/ethernet/mellanox/mlxsw//spectrum_mr.c:655:34-38: ERROR:
invalid reference to the index variable of the iterator on line 636

Fixes: c011ec1bbfd6 ("mlxsw: spectrum: Add the multicast routing offloading logic")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>