tee: optee: log message if dynamic shm is enabled

When dynamic shared memory support is enabled in the OP-TEE Trusted
OS, it doesn't mean that the driver supports it, which can confuse
users during debugging. Log a message when dynamic shared memory is
enabled in the driver, to let users know for sure.

Suggested-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Victor Chong <victor.chong@linaro.org>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>