Changed PPC44x startup message (cpu info, speed...) to common style:

On PPC44x platforms, the startup message generated in "cpu.c" only
comprised the ppc type and revision but not additional informations
like speed etc. Those speed infos where printed in the board specific
code. This new implementation now prints all CPU infos in the common
cpu specific code. No board specific code is needed anymore and
therefore removed from all current 44x implementations.

Patch by Stefan Roese, 27 Nov 2005