Loader GELI support, like lua loader, seems to be broken on PowerPC as
well as on SPARC64 and can cause boot failures even when no encrypted
disks are present. Presumably, the reasons, while unknown, are the same
and most-likely are the result of some endian-unsafe code. Pending
finding the actual problem, extend the blacklist entry for these parts
of loader on SPARC to also cover all PowerPC platforms.

Approved by: re (kib)