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/x86/cpu/efi/app.c b/arch/x86/cpu/efi/app.c
index ba7c02b..1307741 100644
--- a/arch/x86/cpu/efi/app.c
+++ b/arch/x86/cpu/efi/app.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <fdtdec.h>
 #include <netdev.h>