new cpu's for rs6000 target

[Daniel Egger]

Hija,

> Yes, but not extensively.  Mostly it didn't matter much, as you would 
> expect.  Here's Bytemarks before and after (-O3 -funroll-loops 
> -funroll-all-loops -mcpu=750)

I wouldn't expect any differences since you almost didn't touch the 750.
Where we can expect differences is for the higher cpu's and indeed I get
an average of 10% increase in scientific applications and GIMP by just
teaching the maschinedescription about the 7400.

--
Servus,
       Daniel