net: ethtool: Allow write mechanism of LPL and both LPL and EPL

net: ethtool: Allow write mechanism of LPL and both LPL and EPL

CMIS 5.2 standard section 9.4.2 defines four types of firmware update
supported mechanism: None, only LPL, only EPL, both LPL and EPL.

Currently, only LPL (Local Payload) type of write firmware block is
supported. However, if the module supports both LPL and EPL the flashing
process wrongly fails for no supporting LPL.

Fix that, by allowing the write mechanism to be LPL or both LPL and
EPL.

Fixes: c4f78134d45c ("ethtool: cmis_fw_update: add a layer for supporting firmware update using CDB")
Reported-by: Vladyslav Mykhaliuk <vmykhaliuk@nvidia.com>
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Link: https://patch.msgid.link/20240812140824.3718826-1-danieller@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>