There are spelling mistakes in pr_err error messages. Fix them.

Fixes: 4615e5a3 ("optee: add FF-A support")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
[jw: added a fixes]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>