drm/amd/display: incorrect conditions for failing dto calculations

[Why & How]
Previously, when calculating dto phase, we would incorrectly fail when phase
<=0 without additionally checking for the integer value. This meant that
calculations would incorrectly fail when the desired pixel clock was an exact
multiple of the reference clock.

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Clay King <clayking@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Clay King

drivers/gpu/drm/amd/display/dc/dccg/dcn401/dcn401_dccg.c

@@ -619,7 +619,7 @@ void dccg401_set_dp_dto(
 		dto_integer = div_u64(params->pixclk_hz, dto_modulo_hz);
 		dto_phase_hz = params->pixclk_hz - dto_integer * dto_modulo_hz;
 
-		if (dto_phase_hz <= 0) {
+		if (dto_phase_hz <= 0 && dto_integer <= 0) {
 			/* negative pixel rate should never happen */
 			BREAK_TO_DEBUGGER();
 			return;