BACKPORT: tee: indicate privileged dev in gen_caps

Mirrors the TEE_DESC_PRIVILEGED bit of struct tee_desc:flags into struct
tee_ioctl_version_data:gen_caps as TEE_GEN_CAP_PRIVILEGED in
tee_ioctl_version()

Change-Id: Ic3961a07812c3f89a6f3006619d89945733a71a8
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
(cherry picked from commit 059cf566e123ca7eb7434285c6455d7afafb4e02)
Signed-off-by: Victor Chong <victor.chong@linaro.org>