Provide a list of valid protocols for which the driver will provide
it's deferred xmit handler.
When using DSA_TAG_PROTO_KSZ8795 protocol, it does not provide a
"connect" method, therefor ksz_connect() is not allocating ksz_tagger_data.
This avoids the following null pointer dereference:
ksz_connect_tag_protocol from dsa_register_switch+0x9ac/0xee0
dsa_register_switch from ksz_switch_register+0x65c/0x828
ksz_switch_register from ksz_spi_probe+0x11c/0x168
ksz_spi_probe from spi_probe+0x84/0xa8
spi_probe from really_probe+0xc8/0x2d8
Fixes: ab32f56a41 ("net: dsa: microchip: ptp: add packet transmission timestamping")
Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20231206071655.1626479-1-sean@geanix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
1499b89289