battable size

[Ignatios Souvatzis <is%jocelyn.rhein.de@localhost>]

Hello,

currently, the battable size is fixed by the declaration in
powerpc/include/bat.h:

Can we move the battable size to a port-specific file, please? Any suggestions?

[reason:

I need 256 for amigappc. Well, maybe 64 would do.
I need different cache attributes for the ranges

00000000 .. 00ffffff (always i/o region, must be cache inhibited, guarded)
07000000 .. 0fffffff (normal memory) ]

As 0x1000000 .. 0x6ff ffff are not used by Amiga machines, I might be able
to use 64 MB sized slices as well, depending on how the ROM places I/O vs.
memory boards. ]

Regards,
        -is