defconfig: msm: enable fstack-protector-strong

Enable CC_STACKPROTECTOR_STRONG option for msm so that we
can make use of stack protector feature provided by compiler.

Change-Id: Ifa90c00a37b2a4c8d026cd808fa83125655f8d6d
Signed-off-by: Imran Khan <kimran@codeaurora.org>