Provide VINTF for Trusty Keymaster

This makes it easier to add or remove the Trusty keymaster service from
a device by providing a manifest fragment to add whenever it is enabled.

Test: Keymaster VTS, Keystore CTS (sans attestation)
Change-Id: Ib0f5fd7c016c0c18d77c9d2623c89f3b35ba7ad7

trusty/keymaster/4.0/android.hardware.keymaster@4.0-service.trusty.xml

@@ -0,0 +1,11 @@
+<manifest version="1.0" type="device">
+    <hal format="hidl">
+        <name>android.hardware.keymaster</name>
+        <transport>hwbinder</transport>
+        <version>4.0</version>
+        <interface>
+        <name>IKeymasterDevice</name>
+            <instance>default</instance>
+        </interface>
+    </hal>
+</manifest>

trusty/keymaster/Android.bp

@@ -136,4 +136,6 @@ cc_binary {
         "libkeymaster4",
         "android.hardware.keymaster@4.0"
     ],
+
+    vintf_fragments: ["4.0/android.hardware.keymaster@4.0-service.trusty.xml"],
 }