drm/radeon/kms/pm: fix r6xx+ profile setup

This patch is a combination of the previous two profile
patches, but without the index bugs.  It cleans up and
fixes some issues with pm profile setup on r6xx chips.
Some tables have different orderings for the power states,
also, r600 only has 1 clock mode per power state. On
desktop cards there are no battery modes, so the low and high
power states are the same.  For the low profile case, choose
the lower clock mode.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>