GFX PG for Stoney/Carrizo and UVD static PG for Carrizo

[Tom St Denis]

These patches re-enable GFX PG on Stoney and Carrizo.  I've found
that AMD_PG_SUPPORT_CP and AMD_PG_SUPPORT_RLC_SMU_HS are both buggy
so they are disabled.  RLC_SMU_HS results in early system hangs
whereas CP powergating results in harder to trigger system hangs.

With both disabled I've been able to stress test GFX without hangs.

The UVD PG is only enabled if powerplay is disabled.  Tested by 
sampling with the debug tool I can see correct behaviour in the 
PGFSM TILE registers.