Factorize bootstub makefile

Bug: 19708986

This patch aims to remove the huge code duplications in Android.mk and
also add a new kind of bootstub target: ramdump, which is used to boot a
post-crash OS with different memory constraints.

Change-Id: I962b48290994b75a44eb2e47487e1c1a8293f4df
Signed-off-by: Sylvain Chouleur <sylvain.chouleur@intel.com>
7 files changed