add non-executable GNU stack marking on ELF-linux

Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>

lib/loongarch64/efi_stub.S

@@ -1 +1,4 @@
 /* This stub is a stub to make the build happy */
+#if defined(__ELF__) && defined(__linux__)
+       .section .note.GNU-stack,"",%progbits
+#endif