ARM: CPU hotplug: ensure we migrate all IRQs off a downed CPU

Squash following three patches since the patch with 2ef75701 commit
prevents the MSM platforms from booting, which gets solved in the
next commit ca15af19, but adds build failure; which gets solved in the
final commit 78359cb8.

commit 2ef75701
Author: Russell King <rmk+kernel@arm.linux.org.uk>
Date:   Thu Jul 21 14:51:13 2011 +0100

    ARM: CPU hotplug: fix abuse of irqdesc->node

    irqdesc's node member is supposed to mark the numa node number for the
    interrupt.  Our use of it is non-standard.  Remove this, replacing the
    functionality with a test of the affinity mask.

    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

commit ca15af19
Author: Russell King <rmk+kernel@arm.linux.org.uk>
Date:   Thu Jul 21 15:07:56 2011 +0100

    ARM: CPU hotplug: pass in proper affinity mask on IRQ migration

    Now that the GIC takes care of selecting a target interrupt from the
    affinity mask, we don't need all this complexity in the core code
    anymore.  Just detect when we need to break affinity.

    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

commit 78359cb8
Author: Russell King <rmk+kernel@arm.linux.org.uk>
Date:   Thu Jul 21 15:14:21 2011 +0100

    ARM: CPU hotplug: ensure we migrate all IRQs off a downed CPU

    Our selection of interrupts to consider for IRQ migration is sub-
    standard.  We were potentially including per-CPU interrupts in our
    migration strategy, but omitting chained interrupts.  This caused
    some interrupts to remain on a downed CPU.

    We were also trying to migrate interrupts which were not migratable,
    resulting in an OOPS.

    Instead, iterate over all interrupts, skipping per-CPU interrupts
    or interrupts whose affinity does not include the downed CPU, and
    attempt to set the affinity for every one else if their chip
    implements irq_set_affinity().

    Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Change-Id: I1559f4f9b2aa52ce026505c7e4d5e7cf9bd102af
Signed-off-by: Ravi Kumar <kumarrav@codeaurora.org>
[tsoni@codeaurora.org: squash the commits to avoid boot & build failures]
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>