drm/amd/powerplay: raven 4k@60hz dp monitor always flicking

[WHY] clock unit mis-match between caller DC and SMU interface.
      dc pass lock in mhz. the same unit as smu. no covert is needed.

[HOW] remove covert_10k_to_mhz in smu interface
      this fixes corruption issue with 4k @60 display and stutter
      mode enable

Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: hersen wu <hersenxs.wu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>