drm/amd/display: Use calculated disp_clk_khz value for dce110

[Why]

The calculated values for actual disp_clk_khz were ignored when
notifying pplib of the new display requirements. In order to honor DFS
bypass clocks from the hardware, the calculated value should be used.

[How]

The return value for set_dispclk is now assigned back into new_clocks
and correctly carried through into dccg->clks.phyclk_khz. When notifying
pplib of new display requirements dccg->clks.phyclk_khz is used
instead of dce.dispclk_khz. The value of dce.dispclk_khz was never
explicitly set to anything before.

A 15% higher display clock value than calculated is no longer requested
for dce110 since it now makes use of the calculated value.

Since dce112 makes use of dce110's set_bandwidth but not its
update_clocks it needs to have the value correctly carried through.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>