x86/irq: mark NUMA_MIGRATE_IRQ_DESC broken

It causes crash on system with lots of cards with MSI-X
when irq_balancer enabled...

The patches fixing it were both complex and fragile, according
to Eric they were also doing quite dangerous things to the
hardware.

Instead we now have patches that solve this problem via static
NUMA node mappings - not dynamic allocation and balancing.

The patches are much simpler than this method but are still too
large outside of the merge window, so we mark the dynamic balancer
as broken for now, and queue up the new approach for v2.6.31.

[ Impact: deactivate broken kernel feature ]

Reported-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <49E68C41.4020801@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig

@@ -277,6 +277,7 @@ config SPARSE_IRQ
 config NUMA_MIGRATE_IRQ_DESC
 	bool "Move irq desc when changing irq smp_affinity"
 	depends on SPARSE_IRQ && NUMA
+	depends on BROKEN
 	default n
 	---help---
 	  This enables moving irq_desc to cpu/node that irq will use handled.