[media] Rename all public generic RC functions from ir_ to rc_

Those functions are not InfraRed specific. So, rename them to properly
reflect it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/rc/ir-rc6-decoder.c b/drivers/media/rc/ir-rc6-decoder.c
index 2435bbd..88d9487 100644
--- a/drivers/media/rc/ir-rc6-decoder.c
+++ b/drivers/media/rc/ir-rc6-decoder.c
@@ -242,7 +242,7 @@
 			goto out;
 		}
 
-		ir_keydown(dev, scancode, toggle);
+		rc_keydown(dev, scancode, toggle);
 		data->state = STATE_INACTIVE;
 		return 0;
 	}