mei: bus: extend bus API to support command streamer API

Add mei bus API for sending gsc commands: mei_cldev_send_gsc_command()

The GSC commands are originated in the graphics stack
and are in form of SGL DMA buffers.
The GSC commands are synchronous, the response is received
in the same call on the out sg list buffers.
The function setups pointers for in and out sg lists in the
mei sgl extended header and sends it to the firmware.

Signed-off-by: Vitaly Lubart <vitaly.lubart@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220928004145.745803-5-daniele.ceraolospurio@intel.com