Bluetooth: Controller: ISO: Fix issue with removing peripheral data paths

On CIS disconnect, the peripheral will clear all data paths.

However ll_remove_iso_path will fail if attempting to remove a
data path that has not been setup, so if only the CTLR_TO_HOST
direction was set, and the HOST_TO_CTLR bit was set, the
function returned an error and never attempted to clear the other
direction.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>