The flag to enable L2 address learning on egress frames is in CPU header
bit 40, with bit 0 being the leftmost bit of the header. This
corresponds to BIT(7) in the third 16-bit value of the header.
Correctly set L2LEARNING by fixing the off-by-one error.
Fixes: 9eab76c84e31 ("realtek: Improve TX CPU-Tag usage")
Tested-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Signed-off-by: Sander Vanheule <sander@svanheule.net>
d6165ea75b