ANDROID: fix allmodconfig build

commit e0c6791d ("BACKPORT: security: Create "kernel hardening" config area")
introduced an x86 build breakage in allmodconfig mode.
Copying the definition of GCC_PLUGIN_STRUCTLEAK_BYREF_ALL from upstream
version of security/Kconfig.hardening fixes the build.

Change-Id: I2def59283b829b8af8fa343eb1d4ebaa3f2e145d
Reported-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Bug: 143965122
Fixes: e0c6791d ("BACKPORT: security: Create "kernel hardening" config area)
Test: manual - run `make allmodconfig && make -j64`
Signed-off-by: Todd Kjos <tkjos@google.com>