drm/amd/display: Prevent vtotal from being set to 0

[Why]
In dcn314 DML the destination pipe vtotal was being set
to the crtc adjustment vtotal_min value even in cases
where that value is 0.

[How]
Only set vtotal to the crtc adjustment vtotal_min value
in cases where the value is non-zero.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Alan Liu <haoping.liu@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dml/dcn314/dcn314_fpu.c

@@ -295,7 +295,11 @@ int dcn314_populate_dml_pipes_from_context_fpu(struct dc *dc, struct dc_state *c
 		pipe = &res_ctx->pipe_ctx[i];
 		timing = &pipe->stream->timing;
 
-		pipes[pipe_cnt].pipe.dest.vtotal = pipe->stream->adjust.v_total_min;
+		if (pipe->stream->adjust.v_total_min != 0)
+			pipes[pipe_cnt].pipe.dest.vtotal = pipe->stream->adjust.v_total_min;
+		else
+			pipes[pipe_cnt].pipe.dest.vtotal = timing->v_total;
+
 		pipes[pipe_cnt].pipe.dest.vblank_nom = timing->v_total - pipes[pipe_cnt].pipe.dest.vactive;
 		pipes[pipe_cnt].pipe.dest.vblank_nom = min(pipes[pipe_cnt].pipe.dest.vblank_nom, dcn3_14_ip.VBlankNomDefaultUS);
 		pipes[pipe_cnt].pipe.dest.vblank_nom = max(pipes[pipe_cnt].pipe.dest.vblank_nom, timing->v_sync_width);