optee: Remove duplicate 'of' in two places.

file: ./drivers/tee/optee/optee_smc.h
line: 192
 * a2   Size of of SHM
chanegd to
 * a2   Size of SHM

Signed-off-by: Jiang Jian <jiangjian@cdjrlc.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>