Android: use symlinks for driver loading

Android: use symlinks for driver loading

Instead of having special driver loading logic for Android, create
symlinks to gallium_dri.so so we can use the standard loading logic.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>