anv: silence compiler warnings

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/6146
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15387>

src/intel/vulkan/anv_cmd_buffer.c

@@ -618,7 +618,7 @@ void anv_CmdBindPipeline(
    }
 
    default:
-      assert(!"invalid bind point");
+      unreachable("invalid bind point");
       break;
    }