tizen: sd_fusing.py: Switch VF2 board to A/B partition scheme

tizen: sd_fusing.py: Switch VF2 board to A/B partition scheme

Use A/B partition scheme also for VisionFive2 board.

Boot script for VF2 has been updated to discover partitions based on
their GPT name, so it is safe to change layout.

While touching this, lets remove useless 'none' partition, which was
there only to force partitions to have specific numbers, hardcoded
earlier in the boot scripts. Also reduce the size of the 'boot'
partition, as there is nothing so large to store on it.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: If5893114a217dc98766da0afcc925f05b31c0c14