doc-rst: linux_tv: Replace reference names to match ioctls

Due to a limitation at the DocBook language, the references
were using lowercase and slashes, instead of the name of the
ioctls. On ReST, make them identical. This will hopefully
help to cleanup the code a little bit.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/Documentation/linux_tv/media/v4l/vidioc-enuminput.rst b/Documentation/linux_tv/media/v4l/vidioc-enuminput.rst
index 32c8dac..644d506 100644
--- a/Documentation/linux_tv/media/v4l/vidioc-enuminput.rst
+++ b/Documentation/linux_tv/media/v4l/vidioc-enuminput.rst
@@ -1,6 +1,6 @@
 .. -*- coding: utf-8; mode: rst -*-
 
-.. _vidioc-enuminput:
+.. _VIDIOC_ENUMINPUT:
 
 **********************
 ioctl VIDIOC_ENUMINPUT