HID: intel-ish-hid: ISH firmware loader client driver

This driver adds support for loading Intel Integrated Sensor Hub (ISH) firmware
from host file system to ISH SRAM and start execution.

At power-on, the ISH subsystem shall boot to an interim Shim loader-firmware,
which shall expose an ISHTP loader device.

The driver implements an ISHTP client that communicates with the Shim ISHTP
loader device over the intel-ish-hid stack, to download the main ISH firmware.

Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Nick Crews <ncrews@chromium.org>
Tested-by: Jett Rink <jettrink@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>