[media] omap3isp: preview: Fix contrast and brightness handling

Commit bac387efbb88cf0e8df6f46a38387897cea464ee ("omap3isp: preview:
Simplify configuration parameters access") added three fields to the
preview_update structure, but failed to properly update the related
initializers. Fix this.

Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/omap3isp/isppreview.c

···
 		preview_config_contrast,
 		NULL,
 		offsetof(struct prev_params, contrast),
-		0, true,
+		0, 0, true,
 	}, /* OMAP3ISP_PREV_BRIGHTNESS */ {
 		preview_config_brightness,
 		NULL,
 		offsetof(struct prev_params, brightness),
-		0, true,
+		0, 0, true,
 	},
 };