trusty: keymaster: Implement abort

Test: builds
Change-Id: I8dfef740a75ff76aebd3ee63aa747e319193aaed
diff --git a/trusty/keymaster/trusty_keymaster_device.cpp b/trusty/keymaster/trusty_keymaster_device.cpp
index 3f32640..5f16fd0 100644
--- a/trusty/keymaster/trusty_keymaster_device.cpp
+++ b/trusty/keymaster/trusty_keymaster_device.cpp
@@ -626,7 +626,15 @@
 
 keymaster_error_t TrustyKeymasterDevice::abort(keymaster_operation_handle_t operation_handle) {
     ALOGD("Device received abort");
-    return KM_ERROR_OK;
+
+    if (error_ != KM_ERROR_OK) {
+        return error_;
+    }
+
+    AbortOperationRequest request;
+    request.op_handle = operation_handle;
+    AbortOperationResponse response;
+    return Send(KM_ABORT_OPERATION, request, &response);
 }
 
 hw_device_t* TrustyKeymasterDevice::hw_device() {