[media] gspca - sonixj: Fix the darkness of sensor om6802 in 320x240

The images are clearer with a lower bridge clock.
Signed-off-by: NJean-François Moine <moinejf@free.fr>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/sonixj.c

@@ -2532,6 +2532,10 @@ static int sd_start(struct gspca_dev *gspca_dev)
 		if (!mode) {			/* if 640x480 */
 			reg17 &= ~MCK_SIZE_MASK;
 			reg17 |= 0x04;		/* clock / 4 */
+		} else {
+			reg01 &= ~SYS_SEL_48M;	/* clk 24Mz */
+			reg17 &= ~MCK_SIZE_MASK;
+			reg17 |= 0x02;		/* clock / 2 */
 		}
 		break;
 	case SENSOR_OV7630: