Log Message:
update pine64's rockpro64 to latest version from ayufan.

add u-boot package for rock64.  originally this was the same
as the old rockpro64 and works fine on that the rev2.0 board,
but didn't on rev3.0.  the updated version is still has a
problem, but at least gets further and has partition issues
instead of failing to talk to the sd at all.  share a bunch
of the makefile with rockpro64.

for all u-boot, properly fix the subst for tools/dtoc/dtoc.

add both rock64 and rockpro64 to the u-boot meta package and
bump the pkg revision.