peci: Unplugging display from TBT port causes GetTemp() timeouts

[crawfxrd]

• Model: oryp11
• EC version: dd555b9
• OS: Pop!_OS 22.04
• Kernel: 6.2.7-060207-generic

Unplugging a display connected to the TBT port on oryp11 causes PECI GetTemp() timeouts.

Steps to reproduce

1. Plug in a display to the TBT port
2. Power on system, booting to OS
3. Unplug the display
4. Power off or reboot the system

Expected behavior

• System shuts down to S5 or reboots to OS

Actual behavior

• System hangs during shutdown
• peci_get_temp() timeouts are logged by the EC

Additional info

This specifically affects the PECI-over-eSPI implementation, currently only used by oryp11.

Acknowledging the completion in #368 fixed it from hanging on shutdown.

Presumably, this could happen because of

• invalid/insufficient checks in peci_available()
• missing the check to see if a transaction is currently in progress in peci_get_temp()