[media] v4l: mt9v032: Add V4L2 controls for AEC and AGC

This patch adds V4L2 controls for Auto Exposure Control and Auto Gain
Control settings. These settings include low pass filter, update
frequency of these settings and the update interval for those units.

[Avoid forward declarations]
[Fix 80 columns limit violation]
[Rename controls to avoid underscores in names]
[Fix the AEC maximum shutter width on MT9V032]

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>