yam: integer underflow in yam_ioctl()

We cap bitrate at YAM_MAXBITRATE in yam_ioctl(), but it could also be
negative. I don't know the impact of using a negative bitrate but let's
prevent it.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/yam.h

···
 
 struct yamdrv_ioctl_mcs {
 	int cmd;
-	int bitrate;
+	unsigned int bitrate;
 	unsigned char bits[YAM_FPGA_SIZE];
 };