drm/amd/display: guard otg disable w/a for test

[why & how]
HW removed this w/a, but we will still keep it to avoid regression.
but return in test mode.

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Muhammad Ahmed <ahmed.ahmed@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@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/clk_mgr/dcn35/dcn35_clk_mgr.c

@@ -126,6 +126,9 @@ static void dcn35_disable_otg_wa(struct clk_mgr *clk_mgr_base, struct dc_state *
 	struct dc *dc = clk_mgr_base->ctx->dc;
 	int i;
 
+	if (dc->ctx->dce_environment == DCE_ENV_DIAG)
+		return;
+
 	for (i = 0; i < dc->res_pool->pipe_count; ++i) {
 		struct pipe_ctx *old_pipe = &dc->current_state->res_ctx.pipe_ctx[i];
 		struct pipe_ctx *new_pipe = &context->res_ctx.pipe_ctx[i];