drm/amd/display: add set and get clock for testing purposes

add dc_set_clock
add dc_get_clock

this is for testing and diagnostics to get/set DPPCLK and DISPCLK.

Signed-off-by: Charlene Liu <[email protected]>
Reviewed-by: Dmytro Laktyushkin <[email protected]>
Acked-by: Leo Li <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
10 files changed