This deletes the deprecated_registers[] array from regcache.[hc].  I've 
built this on a PPC, and checked all the gdb_mbuild.sh list - the latter 
needed a few tweaks to keep things building, see the ChangeLog for the list.

If anyone listed in the write-after-approval list find's a need to tweak 
something (or updated deprecated_registers), I'd view it as pretty obvious.

committed,
Andrew