media: em28xx-input: improve error handling code

The current I2C error handling logic makes static analyzers
confused:

	drivers/media/usb/em28xx/em28xx-input.c:96 em28xx_get_key_terratec() error: uninitialized symbol 'b'.

Change it to match the coding style we're using elsewhere.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/em28xx/em28xx-input.c

@@ -82,11 +82,16 @@ struct em28xx_IR {
 static int em28xx_get_key_terratec(struct i2c_client *i2c_dev,
 				   enum rc_proto *protocol, u32 *scancode)
 {
+	int rc;
 	unsigned char b;
 
 	/* poll IR chip */
-	if (i2c_master_recv(i2c_dev, &b, 1) != 1)
+	rc = i2c_master_recv(i2c_dev, &b, 1);
+	if (rc != 1) {
+		if (rc < 0)
+			return rc;
 		return -EIO;
+	}
 
 	/*
 	 * it seems that 0xFE indicates that a button is still hold