Flashrom update from Stefan, resolve issue 21

Corresponding to flashrom svn r34 and coreboot v2 svn r2111.
diff --git a/sst28sf040.h b/sst28sf040.h
index ca57eff..027e845 100644
--- a/sst28sf040.h
+++ b/sst28sf040.h
@@ -3,6 +3,6 @@
 
 extern int probe_28sf040(struct flashchip *flash);
 extern int erase_28sf040(struct flashchip *flash);
-extern int write_28sf040(struct flashchip *flash, unsigned char *buf);
+extern int write_28sf040(struct flashchip *flash, uint8_t *buf);
 
 #endif				/* !__SST28SF040_H__ */