Add support for Eon EN25F64

Its ID was spotted in an ICH descriptor region update by Jetway:
http://paste.flashrom.org/view.php?id=1217 and is used on ASUS P8B75-V
boards according to some forum posts (2 chips per board actually).

No datasheet was found, so most values are just guessed from the EN25F32.

Corresponding to flashrom svn r1594.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/flashchips.h b/flashchips.h
index 0fe2cc4..b312587 100644
--- a/flashchips.h
+++ b/flashchips.h
@@ -248,6 +248,7 @@
 #define EON_EN25F80		0x3114
 #define EON_EN25F16		0x3115
 #define EON_EN25F32		0x3116
+#define EON_EN25F64		0x3117	/* guessed */
 #define EON_EN25Q40		0x3013
 #define EON_EN25Q80		0x3014
 #define EON_EN25Q16		0x3015	/* Same as EN25D16 */