heads up new sub-port e500 v2

[Aldy Hernandez]

Stage 3 is open to new ports that do not add extra functionality.  As
such, I will be adding support for a new variant of the e500.

Freescale has a new chip, the 8548, which is essentially the same
as the e500/spe/8540, but with double precision floating point operations
in the registers (full 64-bits).  I'm sure there are plenty of other
goodies, but these are all that affect GCC, and consecuently...me :-).

I will also be working on a 3.4 branch adding support for this chip,
since 3.4 proper is currently closed for such obstrusive changes.  Perhaps
something akin to gcc-3_4-e500-branch.

I'll also be working on the usual glibc+spe changes for those interested.
Binutils support was already added a few weeks ago.

Cheerios.
Aldy