Make bionic's dependency on the tzdata explicit.

Also stop building the obsolete three files, now bionic and libcore
both use the new single file.

Bug: 7012465
Change-Id: I1b9b49af7382c57b6cb8820c2275e6d4044b2bb6
diff --git a/libc/Android.mk b/libc/Android.mk
index cd44f23..e494770 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -878,6 +878,7 @@
 
 LOCAL_MODULE:= libc
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+LOCAL_REQUIRED_MODULES := tzdata
 
 # WARNING: The only library libc.so should depend on is libdl.so!  If you add other libraries,
 # make sure to add -Wl,--exclude-libs=libgcc.a to the LOCAL_LDFLAGS for those libraries.  This