ARM: Kirkwood: handle mv88f6282 cpu in __kirkwood_variant().

ARM: Kirkwood: handle mv88f6282 cpu in __kirkwood_variant().

commit 4089fe95bfed295c8ad38251d5fe02b6b0ba684c upstream.

MPP_F6281_MASK would be previously be returned when on mv88f6282,
which would disallow some valid MPP configurations.

Commit 830f8b91 (arm: plat-orion: fix printing of "MPP config
unavailable on this hardware") made this problem visible as an invalid
MPP configuration is now correctly detected and not applied.

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>