Move multidisplay provider to system_ext

Bug: 140544321

Test: build sdk_gphone_x86-userdebug and sdk_gphone_x86-user
Verify MultiDisplay works.

Change-Id: I4a5c63dec15048914adae4b2e9b1a839feb1632f
diff --git a/MultiDisplayProvider/Android.bp b/MultiDisplayProvider/Android.bp
index 635207d..b0bd438 100644
--- a/MultiDisplayProvider/Android.bp
+++ b/MultiDisplayProvider/Android.bp
@@ -23,4 +23,5 @@
     certificate: "platform",
     resource_dirs: ["res"],
     jni_libs: ["libemulator_multidisplay_jni"],
+    system_ext_specific: true,
 }
diff --git a/MultiDisplayProvider/jni/Android.bp b/MultiDisplayProvider/jni/Android.bp
index 4e8c06c..0fa0b2e 100644
--- a/MultiDisplayProvider/jni/Android.bp
+++ b/MultiDisplayProvider/jni/Android.bp
@@ -34,4 +34,6 @@
         "-Wextra",
         "-Wno-unused-parameter",
     ],
+
+    system_ext_specific: true,
 }