[rfc] drm/radeon/kms: pm debugging check for vbl.

This patch adds a check on avivo chips to see if we are in the VBL
region for the active crtcs when we trigger the engine change.

I appear to have glitches locally on pm transistion (not sure all
fixes are in yet) and this at least seems to be correct here,
maybe others can test on systems with no glitches.

drm/radeon/kms: Convert RV515 to new init path and associated cleanup

Convert the rv515 asic support to new init path also add an explanation
in radeon.h about the new init path. There is also few cleanups
associated with this change (others asic calling rv515 helper
functions).

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

drm/radeon/kms: disable VGA rendering engine before taking over VRAM

Before we use any of VRAM, we need to disable the VGA rendering
engine, this render text mode into a graphical framebuffer
for scanout, however it does this on vblank, and can end up
overwriting the GART table and r600 shader objects.

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

drm/radeon/kms: add r600 KMS support

This adds the r600 KMS + CS support to the Linux kernel.

The r600 TTM support is quite basic and still needs more
work esp around using interrupts, but the polled fencing
should work okay for now.

Also currently TTM is using memcpy to do VRAM moves,
the code is here to use a 3D blit to do this, but
isn't fully debugged yet.

Authors:
Alex Deucher <alexdeucher@gmail.com>
Dave Airlie <airlied@redhat.com>
Jerome Glisse <jglisse@redhat.com>

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