cli: sort_access_points() doesn't take a NULL argument

cli: sort_access_points() doesn't take a NULL argument

The device never returns NULL access point list, it only deallocates it on
dispose(). Make this clear for Coverity:

CID 59387 (#1 of 1): Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking aps suggests that it may be null, but it has
already been dereferenced on all paths leading to the check.