media: rc-core: rename input_name to device_name

When an ir-spi is registered, you get this message.

rc rc0: Unspecified device as /devices/platform/soc/3f215080.spi/spi_master/spi32766/spi32766.128/rc/rc0

"Unspecified device" refers to input_name, which makes no sense for IR
TX only devices. So, rename to device_name.

Also make driver_name const char* so that no casts are needed anywhere.

Now ir-spi reports:

rc rc0: IR SPI as /devices/platform/soc/3f215080.spi/spi_master/spi32766/spi32766.128/rc/rc0

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/rc/redrat3.c b/drivers/media/rc/redrat3.c
index 56d43be..29fa37b 100644
--- a/drivers/media/rc/redrat3.c
+++ b/drivers/media/rc/redrat3.c
@@ -951,7 +951,7 @@
 
 	usb_make_path(rr3->udev, rr3->phys, sizeof(rr3->phys));
 
-	rc->input_name = rr3->name;
+	rc->device_name = rr3->name;
 	rc->input_phys = rr3->phys;
 	usb_to_input_id(rr3->udev, &rc->input_id);
 	rc->dev.parent = dev;