manifest: switch to our libdrm

Change-Id: I268aa07afb764d83ce34503365cf71e4e9131472
diff --git a/omni-aosp.xml b/omni-aosp.xml
index 95edb9c..9de8fd7 100644
--- a/omni-aosp.xml
+++ b/omni-aosp.xml
@@ -26,6 +26,7 @@
     </project>
 
     <project path="external/drm_hwcomposer" name="android_external_drm_hwcomposer" remote="omnirom" revision="android-12.1" />
+    <project path="external/libdrm" name="android_external_libdrm" remote="omnirom" revision="android-12.1" />
 
     <project path="frameworks/av" name="android_frameworks_av" remote="omnirom" revision="android-12.1" />
     <project path="frameworks/base" name="android_frameworks_base" remote="omnirom" revision="android-12.1" />