intel: No error on CreateDevice with unknown extensions.

Layers also export extensions so driver shouldn't generate an error
for extensions that may be for a layer.
diff --git a/icd/intel/dev.c b/icd/intel/dev.c
index e94a85d..f3ffb1b 100644
--- a/icd/intel/dev.c
+++ b/icd/intel/dev.c
@@ -120,10 +120,8 @@
         const enum intel_ext_type ext = intel_gpu_lookup_extension(gpu,
                 info->ppEnabledExtensionNames[i]);
 
-        if (ext == INTEL_EXT_INVALID)
-            return XGL_ERROR_INVALID_EXTENSION;
-
-        dev->exts[ext] = true;
+        if (ext != INTEL_EXT_INVALID)
+            dev->exts[ext] = true;
     }
 
     dev->gpu = gpu;