powerpc: rename immap_86xx.h to fsl_guts.h, and add 85xx support

The immap_86xx.h header file only defines one data structure: the "global
utilities" register set found on Freescale PowerPC SOCs.  Rename this file
to fsl_guts.h to reflect its true purpose, and extend it to cover the "GUTS"
register set on 85xx chips.

Signed-off-by: Timur Tabi <timur@freescale.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>