Fix minor 85xx warnings

Some patches had inserted warnings into the build:
* mpc8560ads declared data without using it
* cpu_init declared ecm and immap without using it in all CONFIGs
* MPC8548CDS.h had its default filenames changed so that they contained
  "\m" in the paths.  Made the defaults not Windows-specific (or
  anything-specific)

Signed-off-by: Andy Fleming <afleming@freescale.com>