Terminate ARC before enabling eARC in the HAL

This is required by the eARC specification: an ARC connection and an
eARC connection cannot exist simultaneously.

The HAL can only initiate an eARC connection once the framework has
informed it with a setEarcEnabled HAL call. The framework waits until
ARC has been terminated to do this.

It's enough to terminate ARC before enabling eARC in the HAL: there is
no need to terminate it again once the HAL reports that eARC is
connected succesfully. Reason: in all situations where the eARC HAL
could report that eARC got connected, ARC has been terminated before:
1. On hotplug in: this means that there was a hotplug out before -->
   eARC is in the IDLE state --> ARC was disconnected when we entered
   the IDLE state.
2. On boot: Both ARC and eARC are disconnected before boot, and on boot,
   eARC gets attempted first.
3. On wake-up: ARC was terminated on the last standby.
4. When eARC gets enabled in the HAL: this CL explicitly terminates ARC.

Bug: 262573690
Test: atest
Change-Id: I91d20fd382c4e4e4102683ace5f2ef55a10e1048