it is introduced by a commit to fix CVE. So remove option '-O2' from
CFLAGS rather than revert the commit to avoid the failure.
[YOCTO #14367]
CC: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Kai Kang <kai.kang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>