intel: fix -Wmaybe-uninitialized warnings
diff --git a/icd/intel/layout.c b/icd/intel/layout.c
index 18bc34c..d1e208c 100644
--- a/icd/intel/layout.c
+++ b/icd/intel/layout.c
@@ -655,7 +655,7 @@
 {
    const XGL_IMAGE_CREATE_INFO *info = params->info;
    XGL_FORMAT format = info->format;
-   bool require_separate_stencil;
+   bool require_separate_stencil = false;
 
    layout->width0 = info->extent.width;
    layout->height0 = info->extent.height;
@@ -1094,6 +1094,11 @@
       }
       hz_height /= 2;
       break;
+   default:
+      assert(!"unknown layout walk");
+      hz_width = 0;
+      hz_height = 0;
+      break;
    }
 
    /*