[media] dib9000: fix return type in dib9000_mbx_send_attr()

dib9000_mbx_send_attr() returns an int.  It doesn't work to save
negative error codes in an unsigned char, so I've made "ret" an int
type.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/dib9000.c

@@ -486,10 +486,11 @@ static int dib9000_mbx_host_init(struct dib9000_state *state, u8 risc_id)
 #define MAX_MAILBOX_TRY 100
 static int dib9000_mbx_send_attr(struct dib9000_state *state, u8 id, u16 * data, u8 len, u16 attr)
 {
-	u8 ret = 0, *d, b[2];
+	u8 *d, b[2];
 	u16 tmp;
 	u16 size;
 	u32 i;
+	int ret = 0;
 
 	if (!state->platform.risc.fw_is_running)
 		return -EINVAL;