sh: Add support SH4 cache control

Add support SH4 cache control and flash_cache function

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

cpu/sh4/cpu.c

diff --git a/cpu/sh4/cpu.c b/cpu/sh4/cpu.c
index 0ebf951..d94e139 100644
--- a/cpu/sh4/cpu.c
+++ b/cpu/sh4/cpu.c
@@ -24,6 +24,7 @@
 #include <common.h>
 #include <command.h>
 #include <asm/processor.h>
+#include <asm/cache.h>
 
 int checkcpu(void)
 {
@@ -51,7 +52,7 @@
 
 void flush_cache (unsigned long addr, unsigned long size)
 {
-
+	dcache_invalid_range( addr , addr + size );
 }
 
 void icache_enable (void)