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>
diff --git a/cpu/mpc85xx/cpu_init.c b/cpu/mpc85xx/cpu_init.c
index 888417f..c7fe130 100644
--- a/cpu/mpc85xx/cpu_init.c
+++ b/cpu/mpc85xx/cpu_init.c
@@ -194,10 +194,12 @@
 
 int cpu_init_r(void)
 {
+#if defined(CONFIG_CLEAR_LAW0) || defined(CONFIG_L2_CACHE)
 	volatile immap_t    *immap = (immap_t *)CFG_IMMR;
+#endif
+#ifdef CONFIG_CLEAR_LAW0
 	volatile ccsr_local_ecm_t *ecm = &immap->im_local_ecm;
 
-#ifdef CONFIG_CLEAR_LAW0
 	/* clear alternate boot location LAW (used for sdram, or ddr bank) */
 	ecm->lawar0 = 0;
 #endif