drm/amdgpu: remove unnecessary rlc reset function on gfx9

The rlc reset function is not necessary during gfx9 initialization/resume phase.
And this function would even cause rlc fw loading failed on some gfx9 ASIC.
Remove this function safely with verification well on Vega/Raven platform.

Signed-off-by: Le Ma <le.ma@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>