omni: add google clock font and use it on ls clock

also switch to Android.bp for font install

Change-Id: Ib8f24f895f319d7321c3ff953c74b6e92d945a0e
diff --git a/prebuilt/fonts/fonts.mk b/prebuilt/fonts/fonts.mk
index f7f508d..69f6749 100644
--- a/prebuilt/fonts/fonts.mk
+++ b/prebuilt/fonts/fonts.mk
@@ -24,4 +24,5 @@
     Muli-SemiBold.ttf \
     Muli-SemiBoldItalic.ttf \
     Muli-Bold.ttf \
-    Muli-BoldItalic.ttf
+    Muli-BoldItalic.ttf \
+    GoogleSansClock-Regular.ttf