drm/nv50/pm: introduce hwsq-based memory reclocking

More work needs to be done on supporting the different memory types.

v2 (Ben Skeggs):
- fixed up conflicts from not having pausing patch first
- restructured code somewhat to fit with how all the other code works
- fixed bug where incorrect mpll_ctrl could get set sometimes
- removed stuff that's cargo-culted from the binary driver
- merged nv92+ display disable into hwsq
- fixed incorrect opcode 0x5f magic at end of ucode

Signed-off-by: Martin Peres <martin.peres@ensi-bourges.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>