gma500: rework register stuff sanely

Rework registers handling to prepare for Medfield.

Signed-off-by: Alan Cox <alan@linux.intel.com>
[split out from a single big patch]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
6 files changed