m68k: mcf5445x: move early ddr init as board-specific

For certain boot types and sbf, for V4 cpu's, an early ddr/sdram init
is required. This patch moves this ddr/sdram early initalization
away from start.S (to be board related).

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
diff --git a/board/freescale/m54455evb/Makefile b/board/freescale/m54455evb/Makefile
index 1c775fa..ecbc3ca 100644
--- a/board/freescale/m54455evb/Makefile
+++ b/board/freescale/m54455evb/Makefile
@@ -6,3 +6,4 @@
 #
 
 obj-y	= m54455evb.o
+extra-y	+= sbf_dram_init.o