V4L/DVB: gspca - sq930x: Change the gain value for Micron sensors

The bit 7 of the sensor gain register multiplies the 7bits value by two.
It is now always set with half the user gain value.
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/sq930x.c

@@ -862,7 +862,7 @@ static void setexposure(struct gspca_dev *gspca_dev)
 		buf[i++] = 0x35;	/* reg = global gain */
 		buf[i++] = 0x00;	/* val H */
 		buf[i++] = sensor->i2c_dum;
-		buf[i++] = sd->gain;	/* val L */
+		buf[i++] = 0x80 + sd->gain / 2; /* val L */
 		buf[i++] = 0x00;
 		buf[i++] = 0x00;
 		buf[i++] = 0x00;