drm/amd/display: fix surface update sequence

An earlier change added update of interdependent dlg/ttu params for pipes
not being updated in the current call. The code fails to check if the other
pipes are actually active yet causing an assert.

This change adds a check for surface presence on the pipes before updating
the interdepenednt params.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Nikola Cornij <Nikola.Cornij@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>