MTK: calling kal_sleep_task in injected task leads to hangs or crashes

[grant-h]

Using kal_sleep_task in MediaTek modkit code can lead to crashes or hangs. The MTK vendor plugin during task injection will overwrite the 0IDLE task: https://github.com/FirmWire/FirmWire/blob/main/firmwire/vendor/mtk/machine.py#L552-L557

This is bad as if VPE 0 goes idle during a sleep call, idle task behavior would be overwritten. Some additional details were provided by the reporter:

The problem seems to stem from the idle tasks (1IDLE, 2IDLE, and 3IDLE); 1 and 3 crash in DCM_Service_Handler_Slave, which expects to be run on a different CPU core. When 1 and 3 are disabled, 2 (which seems to be the "master" for the DCM service) runs in an infinite loop; when all 3 are disabled, nothing appears to run. In any case, my code never resumes from kal_sleep_task.