drm/radeon/kms: Convert R100 to new init path (V2)

New init path allow to simply asic initialization and make easier
to trace what happen on each different asic. We are removing most
callback. More cleanup should happen latter to remove even more
callback. Also cleanup register specific to R100,RV200,RV250.
Version 2 correct the placement on IGP of the VRAM inside GPU address
space to match the stollen RAM placement of IGP.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>