Fix Windows SDK build, add missing dependency

Change-Id: Ic632ec6d526b7913edf90fcca3b8409ebc2ff31a
diff --git a/build/windows_sdk_tools.mk b/build/windows_sdk_tools.mk
index 45d2465..1373613 100644
--- a/build/windows_sdk_tools.mk
+++ b/build/windows_sdk_tools.mk
@@ -9,6 +9,7 @@
 	emulator-arm \
 	emulator-x86 \
 	find_java \
+	find_lock \
 	mksdcard \
 	sdklauncher