drm/amd/powerplay: enable gfxclk ds,dcefclk ds and fw dstate on navi10
on navi10, by default the below four features are enabled.
gfxclk deep sleep: enabled and verified
fw dstate: enabled and then soc ulv is verified
dcefclk deep sleep: enabled and verified. notice that on different boards,
due to the minimum dcefclk deep sleep setting in VBIOS, we may not see dcefclk
deep sleep kicking in.