powerpc: remove dependency on MV64360

The Kconfig entry that allows to "Distribute interrupts on all CPUs by
default" has a (negative) dependency on MV64360. But that Kconfig symbol
was removed in v2.6.27, which means that this dependency has evaluated
to true ever since. It can be removed too.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Scott Wood <scottwood@freescale.com>