Updates to the JH7110 common description:
- add detailed overview of JH-7110 SoC and boot process
- revise descriptions of deprecated StarFive loader modes
- refresh build directions grouped with SPL debug advice
- reduce usage instructions into common methods shared by supported boards
- cite starfive_visionfive2 board maintainer description of StarFive loader
- cite published datasheets for ambient operating temperature data
Redundant/deprecated sections of each board doc are dropped accordingly:
- deepcomputing fml13v01
- milk-v mars
- pine64 star64 (also add inclusion of JH7110 common description)
- visionfive2
Signed-off-by: E Shattow <e@freeshell.de>