media: admin-guide: Fix mgb4 driver documentation structure

Fix the mgb4 driver documentation structure that breaks the
"Video4Linux (V4L) driver-specific documentation" outline.
Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Documentation/admin-guide/media/mgb4.rst

 .. SPDX-License-Identifier: GPL-2.0
 
-====================
-mgb4 sysfs interface
-====================
+The mgb4 driver
+===============
+
+sysfs interface
+---------------
 
 The mgb4 driver provides a sysfs interface, that is used to configure video
 stream related parameters (some of them must be set properly before the v4l2
@@ -12,9 +14,8 @@ There are two types of parameters - global / PCI card related, found under
 ``/sys/class/video4linux/videoX/device`` and module specific found under
 ``/sys/class/video4linux/videoX``.
 
-
 Global (PCI card) parameters
-============================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **module_type** (R):
     Module type.
@@ -42,9 +43,8 @@ Global (PCI card) parameters
 
     where each component is a 8b number.
 
-
 Common FPDL3/GMSL input parameters
-==================================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **input_id** (R):
     Input number ID, zero based.
@@ -190,9 +190,8 @@ Common FPDL3/GMSL input parameters
     *Note: This parameter can not be changed while the input v4l2 device is
     open.*
 
-
 Common FPDL3/GMSL output parameters
-===================================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **output_id** (R):
     Output number ID, zero based.
@@ -282,9 +281,8 @@ Common FPDL3/GMSL output parameters
     Number of video lines between the end of the last valid pixel line (marked
     by DE=1) and assertion of the VSYNC signal. The default value is 2.
 
-
 FPDL3 specific input parameters
-===============================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **fpdl3_input_width** (RW):
     Number of deserializer input lines.
@@ -294,7 +292,7 @@ FPDL3 specific input parameters
     | 2 - dual
 
 FPDL3 specific output parameters
-================================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **fpdl3_output_width** (RW):
     Number of serializer output lines.
@@ -304,7 +302,7 @@ FPDL3 specific output parameters
     | 2 - dual
 
 GMSL specific input parameters
-==============================
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 **gmsl_mode** (RW):
     GMSL speed mode.
@@ -328,10 +326,8 @@ GMSL specific input parameters
     | 0 - disabled
     | 1 - enabled (default)
 
-
-====================
-mgb4 mtd partitions
-====================
+MTD partitions
+--------------
 
 The mgb4 driver creates a MTD device with two partitions:
  - mgb4-fw.X - FPGA firmware.
@@ -344,9 +340,8 @@ also have a third partition named *mgb4-flash* available in the system. This
 partition represents the whole, unpartitioned, card's FLASH memory and one should
 not fiddle with it...
 
-====================
-mgb4 iio (triggers)
-====================
+IIO (triggers)
+--------------
 
 The mgb4 driver creates an Industrial I/O (IIO) device that provides trigger and
 signal level status capability. The following scan elements are available: