tee: amdtee: remove redundant NULL check for pool

Remove NULL check for pool variable, since in the current
code path it is guaranteed to be non-NULL.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/tee/amdtee/core.c

@@ -484,8 +484,7 @@ err_device_unregister:
 	tee_device_unregister(amdtee->teedev);
 
 err_free_pool:
-	if (pool)
-		tee_shm_pool_free(pool);
+	tee_shm_pool_free(pool);
 
 err_kfree_amdtee:
 	kfree(amdtee);