[media] DocBook/media: remove spurious space

Looks ugly, a space before a period at the end of a sentence. Remove it.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Documentation/DocBook/media/v4l/io.xml

@@ -1167,7 +1167,7 @@ will not block anymore, but return an &EPIPE;.</entry>
 	    <entry>The buffer timestamp has been taken from the
 	    <constant>CLOCK_MONOTONIC</constant> clock. To access the
 	    same clock outside V4L2, use
-	    <function>clock_gettime(2)</function> .</entry>
+	    <function>clock_gettime(2)</function>.</entry>
 	  </row>
 	  <row>
 	    <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_COPY</constant></entry>