mapi: Fix Android build

mapi: Fix Android build

The Android build was broken by
    commit ca760181b4420696c7e86aa2951d7203522ad1e8
    Author: Kristian Høgsberg <krh@bitplanet.net>
    Date:   Fri Mar 16 12:55:40 2012 -0400

    shared-glapi: Convert to automake

The offending change was that it redefined the filepaths in sources.mak
like this:
    - FOO_FILES := bar.c
    + FOO_FILES := $(TOP)/src/mapi/mapi/bar.c
This broke the build because source filepaths in Android makefiles must be
relative to the makefile.

Ideally, this could be fixed by reverting the change in sources.mak and
making shared-glapi's Makefile.am use $(addprefix $(TOP)/src/mapi/mapi,
$(FOO_FILES)). However, automake doesn't understand builtin GNU make
functions, such as addprefix. So, it seems that automake and Android can
no longer share sources.mak.

Fix the build by duplicating the source lists from sources.mak into
Android.mk.

Signed-off-by: Chad Versace <chad.versace@linux.intel.com>