Fix load of unet512 vmfb fail on get of iree opts (#1546)

* Change retrieval of Iree options used when loading an existing
unet512 vmfb to look up the "unet" options rather than attempt to
find a non-existent set of options for "unet512"

Co-authored-by: powderluv <powderluv@users.noreply.github.com>

apps/stable_diffusion/src/utils/utils.py

@@ -47,6 +47,7 @@ def get_vmfb_path_name(model_name):
 def _load_vmfb(shark_module, vmfb_path, model, precision):
     model = "vae" if "base_vae" in model or "vae_encode" in model else model
     model = "unet" if "stencil" in model else model
+    model = "unet" if "unet512" in model else model
     precision = "fp32" if "clip" in model else precision
     extra_args = get_opt_flags(model, precision)
     shark_module.load_module(vmfb_path, extra_args=extra_args)