images: updated firmware-only image (20171130)

This image just contains the firmware bits.
It consists of:
- U-Boot SPL v2017.11 (plus a few optional patches)
  - enable A64 arch timer errata workaround
- ARM Trusted Firmware, v1.0-based Allwinner tree with lots of fixes:
  - all the fixes mentioned in the last release, plus:
  - enable the voltage rail for HDMI and the WiFi module
  - fix CPU PLL clock setup
  - fix CPU hotplug (CPU offlining/onlining)
  - adjust Pine64 DDR voltage
  - add SCPI services, triggered via an SMC call:
    - DVFS support (CPU frequency scaling)
    - CPU and GPU temperature sensors support
    - device power plane support (enable/disable AXP power rails)
    - (MMC clock support)
  - read DT name from SPL header to trigger board specific actions
- U-Boot v2017.11, plus a few optional patches:
  - adjust Ethernet driver to cope with new DT binding
  - enable workaround for A64 arch timer errata
  - add poweroff command
  - add 12x22 font and use white background
  - place U-Boot environment in FAT partition
  - update device tree
- A Pine64+ .dtb file capable of running mainline Linux kernels,
  embedded in the U-Boot image (use $fdtcontroladdr).

This image alone boots into U-Boot, but does not come with a kernel or
root file system. It loads arm64 Linux kernels or EFI applications (grub)
from USB devices or SD cards, or via Ethernet using PXE and TFTP.
It can be used to install Linux distributions or to launch mainline kernels.

To make it bootable you should:
- extract and dd onto an uSD card:
  # xzcat pine64_firmware-20171130.img.xz | dd of=/dev/sdX bs=1k seek=8
  (please replace /dev/sdX with the name of your uSD card device file,
  could be /dev/mmcblkX as well)

This firmware image will not boot BSP kernels, as they depend on the
Allwinner proprietary firmware bits (arisc, ATF, U-Boot).