arm64: defconfig: enable OP-TEE

This patch enables configs for Trusted Execution Environment (TEE) and
OP-TEE.

+CONFIG_TEE=y
+CONFIG_OPTEE=y

Signed-off-by: Victor Chong <victor.chong@linaro.org>
Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>