[media] V4L: Add MATRIX option to V4L2_CID_EXPOSURE_METERING control

This patch adds a menu option to the V4L2_CID_EXPOSURE_METERING
control for multi-zone metering.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml
index c8eb6c2..8d7a779 100644
--- a/Documentation/DocBook/media/v4l/controls.xml
+++ b/Documentation/DocBook/media/v4l/controls.xml
@@ -3142,6 +3142,13 @@
 		  <entry><constant>V4L2_EXPOSURE_METERING_SPOT</constant>&nbsp;</entry>
 		  <entry>Measure only very small area at the center of the frame.</entry>
 		</row>
+		<row>
+		  <entry><constant>V4L2_EXPOSURE_METERING_MATRIX</constant>&nbsp;</entry>
+		  <entry>A multi-zone metering. The light intensity is measured
+in several points of the frame and the the results are combined. The
+algorithm of the zones selection and their significance in calculating the
+final value is device dependant.</entry>
+		</row>
 	      </tbody>
 	    </entrytbl>
 	  </row>