net: hsr: Fix typo in the hsr_forward_do() function comment

Correct type in the hsr_forward_do() comment.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>