net: dsa: tag_brcm: legacy: fix pskb_may_pull length

net: dsa: tag_brcm: legacy: fix pskb_may_pull length

[ Upstream commit efdddc4484859082da6c7877ed144c8121c8ea55 ]

BRCM_LEG_PORT_ID was incorrectly used for pskb_may_pull length.
The correct check is BRCM_LEG_TAG_LEN + VLAN_HLEN, or 10 bytes.

Fixes: 964dbf186eaa ("net: dsa: tag_brcm: add support for legacy tags")
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250529124406.2513779-1-noltari@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>