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/rc-loopback.c b/drivers/media/rc/rc-loopback.c
index 62195af..46cc9c2 100644
--- a/drivers/media/rc/rc-loopback.c
+++ b/drivers/media/rc/rc-loopback.c
@@ -219,7 +219,7 @@ static int __init loop_init(void)
 		return -ENOMEM;
 	}
 
-	rc->input_name		= "rc-core loopback device";
+	rc->device_name		= "rc-core loopback device";
 	rc->input_phys		= "rc-core/virtual";
 	rc->input_id.bustype	= BUS_VIRTUAL;
 	rc->input_id.version	= 1;