net: mscc: ocelot: Fix comment in ocelot_vlant_wait_for_completion()

The ocelot_vlant_wait_for_completion() function is very similar to the
ocelot_mact_wait_for_completion(). It seemed to have be copied but the
comment was not updated, so let's fix it.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>