Fix typo in call to gen_selected_ops (pytorch#13072)

### Summary
Wrong variable name used.

### Test plan
Build with EXECUTORCH_SELECT_OPS_YAML option.

Author: Conarnar

CMakeLists.txt

@@ -849,7 +849,7 @@ if(NOT EXECUTORCH_SELECT_OPS_YAML STREQUAL ""
     LIB_NAME
     "executorch_selected_kernels"
     OPS_SCHEMA_YAML
-    "${EXECUTORCH_SELECT_OPS_LIB}"
+    "${EXECUTORCH_SELECT_OPS_YAML}"
     ROOT_OPS
     "${EXECUTORCH_SELECT_OPS_LIST}"
     INCLUDE_ALL_OPS