net: txgbe: distinguish module types by checking identifier

net: txgbe: distinguish module types by checking identifier

Rework txgbe_identify_module() to validate module identifiers through
explicit type checks instead of relying on transceiver_type heuristics.
When using the SFP module, transceiver_type could be a random value,
because it was read from an invalid register.

Fixes: 57d39faed4c9 ("net: txgbe: improve functions of AML 40G devices")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Link: https://patch.msgid.link/20260608070842.36504-3-jiawenwu@trustnetic.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>