media: ov2680: Remove auto-gain and auto-exposure controls

Quoting the OV2680 datasheet:

"3.2 exposure and gain control

In the OV2680, the exposure time and gain are set manually from an external
controller. The OV2680 supports manual gain and exposure control only for
normal applications, no auto mode."

And indeed testing with the atomisp_ov2680 fork of ov2680.c has shown that
auto-exposure and auto-gain do not work.

Note that the code setting the auto-exposure flag was broken, callers
of ov2680_exposure_set() were directly passing !!ctrls->auto_exp->val as
"bool auto_exp" value, but ctrls->auto_exp is a menu control with:

enum  v4l2_exposure_auto_type {
        V4L2_EXPOSURE_AUTO = 0,
        V4L2_EXPOSURE_MANUAL = 1,
	...

So instead of passing !!ctrls->auto_exp->val they should have been passing
ctrls->auto_exp->val == V4L2_EXPOSURE_AUTO, iow the passed value was
inverted of what it should have been.

Also remove ov2680_g_volatile_ctrl() since without auto support the gain
and exposure controls are not volatile.

This also fixes the control values not being properly applied in
ov2680_mode_set(). The 800x600 mode register-list also sets gain,
exposure and vflip overriding the last set ctrl values.

ov2680_mode_set() does call ov2680_gain_set() and ov2680_exposure_set()
but did this before writing the mode register-list, so these values
would still be overridden by the mode register-list.

Add a v4l2_ctrl_handler_setup() call after writing the mode register-list
to restore all ctrl values. Also remove the ctrls->gain->is_new check from
ov2680_gain_set() so that the gain always gets restored properly.

Last since ov2680_mode_set() now calls v4l2_ctrl_handler_setup(), remove
the v4l2_ctrl_handler_setup() call after ov2680_mode_restore() since
ov2680_mode_restore() calls ov2680_mode_set().

Fixes: 3ee47cad ("media: ov2680: Add Omnivision OV2680 sensor driver")
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>