When host system is under heavy load and the NPU is already running
on the lowest frequency, PUNIT may request Duty Cycle Throttling (DCT).
This will further reduce NPU power usage.

PUNIT requests DCT mode using Survabilty IRQ and mailbox register.
The driver then issues a JSM message to the FW that enables
the DCT mode. If the NPU resets while in DCT mode, the driver request
DCT mode during FW boot.

Also add debugfs "dct" file that allows to set arbitrary DCT percentage,
which is used by driver tests.
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Wachowski, Karol <karol.wachowski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240611120433.1012423-7-jacek.lawrynowicz@linux.intel.com