android-constants.c: Move constants to single file.

This patch refactors the sources slightly to reduce dependency
drag between various functions and constant definitions. This
is general cleanup work for future patches.

Change-Id: I5fc0f53f5c933bc89ddf1a43d67a309d03a03c2d
diff --git a/Makefile.common b/Makefile.common
index 2ff49e8..c3f6820 100644
--- a/Makefile.common
+++ b/Makefile.common
@@ -103,6 +103,7 @@
 # Android utility functions
 #
 common_LOCAL_SRC_FILES += \
+	android/android-constants.c \
 	android/async-console.c \
 	android/async-utils.c \
 	android/charmap.c \