lkdtm: add function for testing .rodata section

This adds a function that lives in the .rodata section. The section
flags are corrected using objcopy since there is no way with gcc to
declare section flags in an architecture-agnostic way.

Signed-off-by: Kees Cook <keescook@chromium.org>

drivers/misc/lkdtm.h

@@ -0,0 +1,6 @@
+#ifndef __LKDTM_H
+#define __LKDTM_H
+
+void lkdtm_rodata_do_nothing(void);
+
+#endif