tee: remove unused tee_shm_priv_alloc()

tee_shm_priv_alloc() isn't useful in the current state and it's also not
not used so remove it.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

include/linux/tee_drv.h

@@ -315,18 +315,6 @@ void *tee_get_drvdata(struct tee_device *teedev);
  */
 struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);
 
-/**
- * tee_shm_priv_alloc() - Allocate shared memory privately
- * @dev:	Device that allocates the shared memory
- * @size:	Requested size of shared memory
- *
- * Allocates shared memory buffer that is not associated with any client
- * context. Such buffers are owned by TEE driver and used for internal calls.
- *
- * @returns a pointer to 'struct tee_shm'
- */
-struct tee_shm *tee_shm_priv_alloc(struct tee_device *teedev, size_t size);
-
 /**
  * tee_shm_register() - Register shared memory buffer
  * @ctx:	Context that registers the shared memory