media: v4l2-ctrl: fix flags for DO_WHITE_BALANCE

Control DO_WHITE_BALANCE is a button, with read only and execute-on-write flags.
Adding this control in the proper list in the fill function.

After adding it here, we can see output of v4l2-ctl -L
do_white_balance 0x0098090d (button) : flags=write-only, execute-on-write
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-ctrls.c

@@ -1157,6 +1157,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_FLASH_STROBE_STOP:
 	case V4L2_CID_AUTO_FOCUS_START:
 	case V4L2_CID_AUTO_FOCUS_STOP:
+	case V4L2_CID_DO_WHITE_BALANCE:
 		*type = V4L2_CTRL_TYPE_BUTTON;
 		*flags |= V4L2_CTRL_FLAG_WRITE_ONLY |
 			  V4L2_CTRL_FLAG_EXECUTE_ON_WRITE;