MPC86xx processors are based on the e600 core, which is not the case
in qemu where it is based on the 7400 processor.

This patch creates the e600 core and instantiates the MPC86xx
processors based on it. Therefore, adding the high BATs, the SPRG
4..7 registers, which are e600-specific [1], and a HW MMU model (as 7400).
This allows to define the MPC8610 processor too.

Tested with a kernel using the HW TLB misses.

[1] http://cache.freescale.com/files/32bit/doc/ref_manual/E600CORERM.pdfSigned-off-by: NJulio Guerra <guerr@julio.in>
Signed-off-by: NAlexander Graf <agraf@suse.de>