arm64: defconfig: disable plain NEON implementation of AES

The plain NEON implementation of AES is only suited for v8 cores that lack
the ARMv8 Crypto Extensions but have an implementation of the NEON tbl/tbx
instruction that is not pathetically slow. Unfortunately, this is currently
the empty set, so there is no point in including this implementation by
default. So disable it.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>