drm/amd/display: Re-initialize viewport after pipe merge

[Why]
Pipes get merged in preparation for SubVP but if they don't get used, and
are in ODM or some other multi pipe config, it would calculate the
voltage level with a viewport of just one pipe from when they were split
resulting in too low of a voltage level.

[How]
Made it so that the viewport and other timing settings get rebuilt and re-
initialized after the pipe merge, before calculating the voltage level so it
would calculate it correctly.

Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Brian Chang <Brian.Chang@amd.com>
Signed-off-by: Ethan Wellenreiter <Ethan.Wellenreiter@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/dcn32/dcn32_fpu.c

@@ -1024,6 +1024,15 @@ static void dcn32_full_validate_bw_helper(struct dc *dc,
 	    dc->debug.force_subvp_mclk_switch)) {
 
 		dcn32_merge_pipes_for_subvp(dc, context);
+		// to re-initialize viewport after the pipe merge
+		for (int i = 0; i < dc->res_pool->pipe_count; i++) {
+			struct pipe_ctx *pipe_ctx = &context->res_ctx.pipe_ctx[i];
+
+			if (!pipe_ctx->plane_state || !pipe_ctx->stream)
+				continue;
+
+			resource_build_scaling_params(pipe_ctx);
+		}
 
 		while (!found_supported_config && dcn32_enough_pipes_for_subvp(dc, context) &&
 			dcn32_assign_subvp_pipe(dc, context, &dc_pipe_idx)) {