[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/video/ir-kbd-i2c.c b/drivers/media/video/ir-kbd-i2c.c
index 83662a4..c77ea53 100644
--- a/drivers/media/video/ir-kbd-i2c.c
+++ b/drivers/media/video/ir-kbd-i2c.c
@@ -252,7 +252,7 @@
 	}
 
 	if (rc)
-		ir_keydown(ir->rc, ir_key, 0);
+		rc_keydown(ir->rc, ir_key, 0);
 }
 
 static void ir_work(struct work_struct *work)