[media] v4l: Fix minor typos in the documentation

Signed-off-by: Sylwester Nawrocki <snjw23@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/subdev-formats.xml

@@ -2525,7 +2525,7 @@
 
       <para>Those data formats consist of an ordered sequence of 8-bit bytes
 	obtained from JPEG compression process. Additionally to the
-	<constant>_JPEG</constant> prefix the format code is made of
+	<constant>_JPEG</constant> postfix the format code is made of
 	the following information.
 	<itemizedlist>
 	  <listitem><para>The number of bus samples per entropy encoded byte.</para></listitem>