common: Move checkcpu() out of common.h

This function belongs in cpu_func.h so move it over.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/sh/cpu/sh4/cpu.c b/arch/sh/cpu/sh4/cpu.c
index a8b50a9..ee36aca 100644
--- a/arch/sh/cpu/sh4/cpu.c
+++ b/arch/sh/cpu/sh4/cpu.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <cpu_func.h>
 #include <netdev.h>
 #include <asm/processor.h>