[media] Make nchg variable signed because the code compares this variable against negative values

The sonixj driver compares the value for nchg with:
if (sd->nchg < -6 || sd->nchg >= 12) {

With u8, negative values won't work.

Signed-off-by: Hans Petter Selasky <[e-mail]>
Acked-by: Jean-Francois Moine <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/gspca/sonixj.c

···
 
 	u32 pktsz;			/* (used by pkt_scan) */
 	u16 npkt;
-	u8 nchg;
+	s8 nchg;
 	s8 short_mark;
 
 	u8 quality;			/* image quality */