optee: Fix memory leak when failing to register shm pages

commit ec185dd3ab257dc2a60953fdf1b6622f524cc5b7 upstream.

Free the previously allocated pages when we encounter an error condition
while attempting to register the pages with the secure world.

Fixes: a249dd200d03 ("tee: optee: Fix dynamic shm pool allocations")
Fixes: 5a769f6ff439 ("optee: Fix multi page dynamic shm pool alloc")
Cc: stable@vger.kernel.org
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>