arm-trusted-firmware-sunxi: move to use the common tf-a build code and bump to latest...

arm-trusted-firmware-sunxi: move to use the common tf-a build code and bump to latest version

Create a -a64 package for now. Moving to the latest ATF was tested on a
SoPine A64 board.

U-Boot SPL 2020.04 (Feb 19 2021 - 11:28:19 +0000)
DRAM: 2048 MiB
Trying to boot from MMC1
NOTICE:  BL31: v2.4(release):reboot-15854-g42b39a13d2
NOTICE:  BL31: Built : 22:45:53, Feb 22 2021
NOTICE:  BL31: Detected Allwinner A64/H64/R18 SoC (1689)
NOTICE:  BL31: Found U-Boot DTB at 0x4090a28, model: SoPine with baseboard
NOTICE:  PSCI: System suspend is unavailable

U-Boot 2020.04 (Feb 19 2021 - 11:28:19 +0000) Allwinner Technology

CPU:   Allwinner A64 (SUN50I)
Model: SoPine with baseboard
DRAM:  2 GiB

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>