media: staging: ipu3-imgu: add the AWB memory layout

media: staging: ipu3-imgu: add the AWB memory layout

While parsing the RAW AWB metadata, the AWB layout was missing to fully
understand which byte corresponds to which feature. Make the field names
and usage explicit, as it is used by the userspace applications.

[Sakari Ailus: Changed wording of sat_ratio field as per review comments,
	       fixed a whitespace issue.]

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Bingbu Cao <bingbu.cao@intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>