Update Android.mk to build Chromium OS changes.

The merged CLs from Chromium OS include a new dependency in
libdivsufsort and split some source files. This patch includes changes
to the Android.mk to build with the new CLs.

Bug: 24332905
Change-Id: Id7cc128bc7527e2c1eadc2319dd249e5746a903f
Test: mmm external/bsdiff; make otatools
3 files changed