x86/apic/noop: Tidy up the code

x86/apic/noop: Tidy up the code

First of all apic_noop can't be probed because it's not registered. So
there is no point for implementing a probe callback. The machine is
rightfully to die when that is invoked.

Remove the gunk and tidy up the other space consuming dummy callbacks.

This gunk should simply die. Nothing should ever invoke APIC callbacks once
this is installed, But that's a differrent story for another round of
cleanups. The comment on top of this file which was intentionally left in
place tells exactly why this is needed: voodoo programming.

In fact the kernel of today should just outright refuse to boot on a system
with no (functional) local APIC. That would spare tons of #ifdeffery and
other nonsense.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)