staging: android: binder: Add binder compat layer

This patch adds support for 32bit userspace running on 64bit kernels.
All the changes done in this patch have been tested on 32bit and 64bit
systems.

Change-Id: Ib4cf5590579c3c7fa60d390cefc06780c5be390f
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Git-commit: 16305458cda7088bb0da021d602c6d8fbb642bda
Git-repo: git://linux-arm.org/linux-2.6-armdroid.git


[ohaugan@codeaurora.org: Merging with msm-specific changes]
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>