BACKPORT: tee: optee: store OP-TEE capabilities in private data

Those capabilities will be used in subsequent patches.

Change-Id: I296269714687d346c7beaf30fa400d74c81e717a
Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
(cherry picked from commit d885cc5e0759fc19badadddb60a64344b551469b)
Signed-off-by: Victor Chong <victor.chong@linaro.org>