ARM: ixp4xx: Move NPE and QMGR to drivers/soc

The Network Processing Engine and Queue Manager are
versatile firmware components used by several IXP4xx
drivers.

Drivers are relying on getting access to these components
using <mach/*> headers which does not work with
multiplatform. We need to find a better place for the
drivers to live.

Let's first move them to drivers/soc and the start to
refactor a bit by passing resources and moving headers.

This patch introduce static IRQ assignments but that
will be fixed by later patches in this series.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>