media: bttv-input: better handle errors at I2C transfer

The error handling logic at get_key_pv951() is a little bit
akward, with produces this false positive warning:

	drivers/media/pci/bt8xx/bttv-input.c:344 get_key_pv951() error: uninitialized symbol 'b'.

Do a cleanup. As a side effect, it also improves its coding
style.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/pci/bt8xx/bttv-input.c

@@ -332,11 +332,15 @@ static void bttv_ir_stop(struct bttv *btv)
 static int get_key_pv951(struct IR_i2c *ir, enum rc_proto *protocol,
 			 u32 *scancode, u8 *toggle)
 {
+	int rc;
 	unsigned char b;
 
 	/* poll IR chip */
-	if (1 != i2c_master_recv(ir->c, &b, 1)) {
+	rc = i2c_master_recv(ir->c, &b, 1);
+	if (rc != 1) {
 		dprintk("read error\n");
+		if (rc < 0)
+			return rc;
 		return -EIO;
 	}