POWERPC: Add cpm2 stuff support to the fsl_soc.c

This patch contains necessary modifications to support the CPM2 SoC peripherals.
For the time being, those are fs_enet Ethernet driver and cpm_uart serial.
Written initially to support mpc8560, it also suites to the part of the large PQ2
(more specifically, mpc8260) family.

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