accel/amdxdna: Treat power-off failure as unrecoverable error

accel/amdxdna: Treat power-off failure as unrecoverable error

Failing to set power off indicates an unrecoverable hardware or firmware
error. Update the driver to treat such a failure as a fatal condition
and stop further operations that depend on successful power state
transition.

This prevents undefined behavior when the hardware remains in an
unexpected state after a failed power-off attempt.

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20251106180521.1095218-1-lizhi.hou@amd.com