Add SST49LF020 support

Corresponding to flashrom svn r373 and coreboot v2 svn r3850.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/flash.h b/flash.h
index 06156dc..282a44d 100644
--- a/flash.h
+++ b/flash.h
@@ -356,6 +356,7 @@
 #define SST_39VF040		0xD7
 #define SST_49LF040B		0x50
 #define SST_49LF040		0x51
+#define SST_49LF020		0x61
 #define SST_49LF020A		0x52
 #define SST_49LF080A		0x5B
 #define SST_49LF002A		0x57