documentation: update after TARGET_DEVICE_TABLE removal

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

docs/buildroot.html

@@ -661,16 +661,6 @@ endif
 	<code>$(BOARD_PATH)/target_skeleton</code> so that the target
 	skeleton is stored in the board specific directory.</li>
 
-	<li><code>TARGET_DEVICE_TABLE</code> to a file that contains
-	the target device table &mdash; the list of device files (in
-	<code>/dev/</code>) to be created by the root filesystem build
-	procedure. If this variable is defined, the given device table
-	will be used instead of the default one. If defined, the
-	convention is to define it to
-	<code>$(BOARD_PATH)/target_device_table.txt</code>. See
-	<code>target/generic/device_table.txt</code> for an example
-	file.</li>
-
       </ul>
 
       </li>