fix PDK no-java build

- As this component is in PDK, it should not be built when necessary
  frameworks libraries are not available.
- For full platform source tree, the ...JAVA_SUPPORT_LEVEL is platform.

Change-Id: I6d37970ab7a3e5183d3a04b003ec3f81f907abc8

Android.mk

@@ -12,6 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# enable this build only when platform library is available
+ifeq ($(TARGET_BUILD_JAVA_SUPPORT_LEVEL),platform)
+
 LOCAL_PATH := $(call my-dir)
 
 include $(CLEAR_VARS)
@@ -31,3 +34,4 @@ include $(BUILD_JAVA_LIBRARY)
 # ============================================================
 include $(call all-makefiles-under,$(LOCAL_PATH))
 
+endif # JAVA platform