[media] buffer.rst: Adjust table columns for LaTeX output

The table columns are not properly displayed. Also, some
tables are too big to fit into just one page. So, fix them,
in order to better display the tables.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/uapi/v4l/buffer.rst

@@ -39,12 +39,14 @@ buffer.
 struct v4l2_buffer
 ==================
 
-.. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}|
+.. tabularcolumns:: |p{1.3cm}|p{2.5cm}|p{1.3cm}|p{12.0cm}|
+
+.. cssclass:: longtable
 
 .. flat-table:: struct v4l2_buffer
     :header-rows:  0
     :stub-columns: 0
-    :widths:       1 1 1 2
+    :widths:       1 2 1 10
 
 
     -  .. row 1
@@ -286,6 +288,8 @@ struct v4l2_plane
 
 .. tabularcolumns:: |p{3.5cm}|p{3.5cm}|p{3.5cm}|p{7.0cm}|
 
+.. cssclass:: longtable
+
 .. flat-table::
     :header-rows:  0
     :stub-columns: 0
@@ -403,12 +407,14 @@ struct v4l2_plane
 enum v4l2_buf_type
 ==================
 
-.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+.. cssclass:: longtable
+
+.. tabularcolumns:: |p{7.2cm}|p{0.6cm}|p{9.7cm}|
 
 .. flat-table::
     :header-rows:  0
     :stub-columns: 0
-    :widths:       3 1 4
+    :widths:       4 1 9
 
 
     -  .. row 1
@@ -519,7 +525,9 @@ enum v4l2_buf_type
 Buffer Flags
 ============
 
-.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+.. tabularcolumns:: |p{7.0cm}|p{2.2cm}|p{8.3cm}|
+
+.. cssclass:: longtable
 
 .. flat-table::
     :header-rows:  0
@@ -953,7 +961,7 @@ Timecode Types
 Timecode Flags
 --------------
 
-.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+.. tabularcolumns:: |p{6.6cm}|p{1.4cm}|p{9.5cm}|
 
 .. flat-table::
     :header-rows:  0