staging: vchiq_arm: Add compatibility wrappers for ioctls

staging: vchiq_arm: Add compatibility wrappers for ioctls

This patch adds compatibility wrappers for the ioctls
exposed by vchiq/vc04_services.  The compat ioctls are
completely implemented on top of the native ioctls.  No
existing lines are modified.

While the ideal approach would be to cleanup the existing
code, this path is simplier and easier to review. While
it does have a small runtime performance penality vs
seperating the existing code into wrapper+worker functions,
the penality is small since only the metadata is copied
back onto the 32 bit user mode stack.

The on top of approach is the approach used by several
existing performance critical subsystems of Linux such
as the DRM 3D graphics subsystem.

Testing:

1. A 32 bit chroot was created on a RPI 3 and vchiq_test
was built for armhf.  The usual tests were run such as
vchiq_test -f 10 and vchiq_test -p.

2. This patch was copied onto the shipping version of
the Linux kernel used for the RPI and that kernel was
built for arm64. That kernel was used to boot Raspbian.
Many of the builtin features are now functional such
as the "hello_pi" examples, and minecraft_pi.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>