perf: Add cache_l1d perf event support

This patch adds support and documentation for
a generalized hardware cache event called cache_l1d
perf event.

Signed-off-by: Nitesh Konkar <nitkon12@linux.vnet.ibm.com>

docs/formatdomain.html.in

@@ -1937,6 +1937,7 @@
   <event name='stalled_cycles_frontend' enabled='no'/>
   <event name='stalled_cycles_backend' enabled='no'/>
   <event name='ref_cpu_cycles' enabled='no'/>
+  <event name='cache_l1d' enabled='no'/>
 </perf>
 ...
 </pre>
@@ -2015,6 +2016,12 @@
          by applications running on the platform</td>
       <td><code>perf.ref_cpu_cycles</code></td>
     </tr>
+    <tr>
+      <td><code>cache_l1d</code></td>
+      <td>the count of total level 1 data cache by applications running on
+           the platform</td>
+      <td><code>perf.cache_l1d</code></td>
+    </tr>
   </table>
 
     <h3><a name="elementsDevices">Devices</a></h3>