kasan: disable kasan during unwind_frame()

Disable kasan during unwind_frame() as current version
of LLVM is not supporting following compiler attribute:
__attribute__((no_sanitize("address"))).

Change-Id: I600efd6c68efc3dbf4f6ed2acbd320f8c6038b69
Signed-off-by: Prateek Sood <prsood@codeaurora.org>