net: mscc: fix the alignment in ocelot_port_fdb_del()

align the extack argument of the ocelot_port_fdb_del()
function.
Signed-off-by: Alaa Mohamed <eng.alaamohamedsoliman.am@gmail.com>
Link: https://lore.kernel.org/r/20220520002040.4442-1-eng.alaamohamedsoliman.am@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>