[Why]
Users would like more accurate pixel clocks, especially for fractional
"TV" frame rates like 59.94 Hz.

[How]
Store and communicate pixel clocks with 100 Hz accuracy from
dc_crtc_timing through to BIOS command table setpixelclock call.
Signed-off-by: Ken Chalmers <ken.chalmers@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>