idle: Remove unused ARCH_HAS_DEFAULT_IDLE

The Kconfig symbol ARCH_HAS_DEFAULT_IDLE is unused. Commit
a0bfa1373859e9d11dc92561a8667588803e42d8 ("cpuidle: stop
depending on pm_idle") removed the only place were it was
actually used. But it did not remove its Kconfig entries (for sh
and x86). Remove those two entries now.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Len Brown <len.brown@intel.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Link: http://lkml.kernel.org/r/1363869683.1390.134.camel@x61.thuisdomein
Signed-off-by: Ingo Molnar <mingo@kernel.org>