m68k: add dspi chip-select support

Signed-off-by: Angelo Dureghello <angelo@sysam.it>

Changes for v5:
- new patch
diff --git a/arch/m68k/cpu/mcf5227x/start.S b/arch/m68k/cpu/mcf5227x/start.S
index e1b6c35..61f9c68 100644
--- a/arch/m68k/cpu/mcf5227x/start.S
+++ b/arch/m68k/cpu/mcf5227x/start.S
@@ -378,7 +378,8 @@
 	clr.l	%sp@-
 
 	/* run low-level board init code (from flash) */
-	bsr	board_init_f
+	move.l	#board_init_f, %a1
+	jsr	(%a1)
 
 	/* board_init_f() does not return */