POWERPC: Add support for the mpc8560 eval board

This makes the 8560 evaluation board fully supported under arch/powerpc,
as the first board with CPM2 SoC peripherals. The brand new devicetree
nodes are introduced (intending to be a subset of the QuiccEngine-equipped
models, with dts sources placed into the kernel according to the new convention.

Assuming all the preceding stuff applied (PAL+fs_enet related+ CPM_UART
update), the both TSEC eth ,FCC Eths, and both SCC UARTs are
working. The relevant drivers are still capable to drive users in ppc,
which was verified with 8272ADS (SCC uart+FCC eth).

This is also verified on mpc8540 and actually make it work (PCI stuff
working as well)

Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>