pseries: Update SLOF firmware image

pseries: Update SLOF firmware image

SLOF git commit is e2e8ac901e617573ea383f9cffd136146d0675a4

The main changes are:
* fixed bug with not passing arguments from -append
* client-architecture-support hypercall
* netboot
* USB stack fixes

The full list of changes:
  > client-architecture-support: fix wrong version read
  > client-architecture-support: fix redundant stack drop
  > Update device tree returned by CAS hypercall
  > fdt: introduce fdt-init
  > Add ibm,client-architecture-support method
  > Kernel parameter passed from qemu commandline ignored
  > Allow more than one client to open net devices simultaneously
  > ci: add missing close in else condition
  > Add GPT support
  > pci: fix interrupt-map for bridges
  > usb-ohci: preserve the toggleCarry bit in ED
  > usb-ohci: done_head processing fixes
  > usb-ohci: update init and rationalize timings
  > usb-msc: handle stall and other fixes
  > scsi: make probe more error resilient
  > usb-core: Add CLEAR FEATURE api
  > Implement range allocator
  > Remove bcm57xx network driver as module
  > Remove e1000 network driver as module
  > Remove virtio-net network driver as module
  > Remove veth network driver as module
  > Add missing close-dev in ping
  > Remove lodable network driver modules and related functions
  > Add bcm57xx network driver in libbcm
  > Add e1000 network driver in libe1k
  > Add virtio-net driver in libvirtio
  > Add veth driver in libveth
  > Get MAC address for client interface module
  > Add SLOF usleep wrapper
  > Add SLOF pci wrapper functions
  > Fix 'canon' client interface

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>