Documentation: networking: dsa: Update tagging protocols

Add Qualcomm QCA tagging introduced in cafdc45c to the
list of supported protocols.

Signed-off-by: Fabian Mewes <architekt@coding4coffee.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>