sunxi sysupgrade was based on the x86 implementation; sync fixes and other
changes from the current x86 version:
x86: fix sysupgrades on disks with 4k block size
x86: sysupgrade: move partition table change check to platform_check_image
x86: sysupgrade: refactor platform_do_upgrade
x86: sysupgrade: explicitly rescan disk after writing partition table
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>