binding: rename descriptor region to descriptor pool

This should be trivial, except that the intel driver has intel_desc_pool
internally.  Exchange the names of intel_desc_pool and intel_desc_region.
diff --git a/icd/intel/obj.c b/icd/intel/obj.c
index 145e463..edb04e4 100644
--- a/icd/intel/obj.c
+++ b/icd/intel/obj.c
@@ -184,9 +184,9 @@
         /* TODO */
         shallow_copy = sizeof(XGL_DESCRIPTOR_SET_LAYOUT_CREATE_INFO) * 0;
         break;
-    case XGL_DBG_OBJECT_DESCRIPTOR_REGION:
-        assert(info.header->struct_type ==  XGL_STRUCTURE_TYPE_DESCRIPTOR_REGION_CREATE_INFO);
-        shallow_copy = sizeof(XGL_DESCRIPTOR_REGION_CREATE_INFO);
+    case XGL_DBG_OBJECT_DESCRIPTOR_POOL:
+        assert(info.header->struct_type ==  XGL_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO);
+        shallow_copy = sizeof(XGL_DESCRIPTOR_POOL_CREATE_INFO);
         break;
     default:
         assert(!"unknown dbg object type");