pseries: interrupt controller should not have a 'reg' property

The interrupt controller presented in the device tree for the pseries
machine is manipulated by the guest only through hypervisor calls.  It
has no real or emulated registers for the guest to access.

However, it currently has a bogus 'reg' property advertising a register
window.  Moreover, this property has an invalid format, being a 32-bit
zero, when the #address-cells property on the root bus indicates that it
needs a 64-bit address.  Since the guest never attempts to manipulate
the node directly, it works, but it is ugly and can cause warnings when
manipulating the device tree in other tools (such as future firmware
versions).

This patch, therefore, corrects the problem by entirely removing the
interrupt-controller node's 'reg' property.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
