pseries: Update SLOF firmware image to qemu-slof-20140404

pseries: Update SLOF firmware image to qemu-slof-20140404

The change log is:
  > Isolate sc 1 detection logic
  > build: auto-detect ppc64 architecture
  > cas: increase hcall buffer size to accomodate 256 cpus
  > usb: change device tree naming
  > usb-core: adjust port numbers in set_address
  > virtio-scsi: correct srplun comment
  > Fix kernel loading
  > Workaround to make grub2 assign server ip from dhcp ack packet only
  > ELF: Enter LE binary in LE mode
  > ELF loading should fail for virt != phys

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