Move utility functions into new source files

Corresponding to flashrom svn r6 and coreboot v2 svn r1428.
diff --git a/sst39sf020.c b/sst39sf020.c
index 65fc623..fa35276 100644
--- a/sst39sf020.c
+++ b/sst39sf020.c
@@ -32,7 +32,7 @@
 
 #define AUTO_PG_ERASE1		0x20
 #define AUTO_PG_ERASE2		0xD0
-#define AUTO_PGRM			0x10
+#define AUTO_PGRM		0x10
 #define CHIP_ERASE		0x30
 #define RESET			0xFF
 #define READ_ID			0x90