Reboot and auto reconnect will loading for a long time when APM set CAN_P1_DRIVER to 1

#### Issue details
In current Ardupilot master branch if compile with copter, when set `CAN_P1_DRIVER` or `CAN_P2_DRIVER` to `1` and send a reboot command to autopilot, Mission Planner will reconnect automaticlly and enter a infinite loading state just like that:

In order to exit this loading state, you must disconnect and reconnect manually in MP, or click the Retry Now button in `CONFIG` tabs. When MP staying in the loading state, the console window shows that it reading a 'None' param. This issue will not occur if APM changes `GPS1_TYPE` to any value. But if reset all paramters to default, this issue will reappear.

I guess it might be a MP issue, see https://github.com/ArduPilot/ardupilot/issues/27608.

#### Version
ArduCopter V4.6.0-dev
Mission Planner 1.3.81 build 1.3.8741.25556

#### Platform
[ ] All
[ ] AntennaTracker
[ x ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type
Copter

#### Logs
no logs.

Reproduce with ArduCopter V4.6.0-dev and Mission Planner 1.3.81 while CAN_P1_DRIVER or CAN_P2_DRIVER is set to 1, then reboot and observe the automatic reconnect, CONFIG tab, and MP console. Compare behavior after changing GPS1_TYPE and after resetting parameters to defaults, and review the related ArduPilot issue. Done means automatic reconnect no longer remains in the infinite loading state and manual retry is unnecessary.

Written by the indexing model from the issue text.