wifi: iwlwifi: mld: don't modify trans state where not needed

wifi: iwlwifi: mld: don't modify trans state where not needed

In suspend and resume flows, if we had any error we set the transport state to
'FW_ERROR' This was done to avoid sending commands when we shouldn't.

In the mentioned flows, we can have a few types of errors:
1. logic errors
2. FW is in error state (can't send commands)
3. FW is misbehaving
4. D3 handshake error

In the first, we can still talk to the firmware.
In the second - the transport already knows about the FW error, no need to tell it.
In the third - we need to treat it as any other FW misbehaviour. There is no reason
to have a special handling here.

So we only need it for the last type. Change the code to set the
tansport state to FW error only in case of a d3 handshake error.

While at it, add a comment explaining why the opmode sets the FW error
bits.

Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250826184046.44c74ac0eb2a.Ic7369e622d908684f9b25ffc293d14c167c26414@changeid