merge geom redboot and map

[rozhuk.im at gmail.com]

> > I need your opinions, suggestions and help with testing and including
> code
> > to main stream source tree.
> 
> I think this likely is a good refactoring.
> 
> > PS: I can test only "map" part on my Agestar LB2.
> 
> But please make sure FIS still works.

I hope peoples with redboot hardware help with testing.


Another question is path to mapped block (partition)?

Now
- redboot: /dev/redboot/%name
- map: /dev/map/%name

Variants:
1. stay as is
2. /dev/flash/%name
3. ?