Move utility functions into new source files

Corresponding to flashrom svn r6 and coreboot v2 svn r1428.
diff --git a/flash.h b/flash.h
index f4a3d22..6cf911e 100644
--- a/flash.h
+++ b/flash.h
@@ -55,5 +55,6 @@
 #define MSYSTEMS_MD2802   0x30 /* hmm -- both 0x30 */
 
 extern void myusec_delay(int time);
-
+extern void myusec_calibrate_delay();
+extern int enable_flash_write(void);
 #endif /* !__FLASH_H__ */