Moved fdt command support code to fdt_support.c

...in preparation for improving the bootm command's handling of fdt blobs.
Also cleaned up some coding sloppiness.
diff --git a/cpu/mpc83xx/cpu.c b/cpu/mpc83xx/cpu.c
index 21b1646..aa4d9b1 100644
--- a/cpu/mpc83xx/cpu.c
+++ b/cpu/mpc83xx/cpu.c
@@ -364,6 +364,7 @@
 			/*
 			 * If unconditional create or the property already exists...
 			 */
+			err = 0;
 			if ((fixup_props[j].createflags & FT_CREATE) ||
 				(fdt_get_property(fdt, nodeoffset, fixup_props[j].prop, 0))) {
 				if (fixup_props[j].createflags & FT_BUSFREQ) {