drm/amd/display: Remove the check to see if pp_display_cfg is changed

[Why]
When going to full-screen mode commit_planes_for_stream tries to decrease
dcf_deep_sleep value, but safe_to_lower is false, so we don't send the new value
to SMU but dc context gets updated.
Later when dc_post_update_surfaces_to_stream tries to lower dcf_ds when
safe_to_lower is true, this check prevents the message from being sent.

[How]
Remove the check that compares new value with what is stored in dc_context.
This check is not necessary as dcn1_update_clocks already checks if the value
is different from the current dcf_dp value.

Signed-off-by: Fatemeh Darbehani <fatemeh.darbehani@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>