flashchips: Add Macronix MX25U51245G

Copy 'n paste support for Macronix MX25U51245G. I don't pretend to know
a whole lot about SPI FLASH so its mostly copied from other MX25U devices
and double checked a few bits and pieces against the datasheet.

I have tested basic probe, read, erase and write using layout files. I
tested both with 4MB@0x0000000 and 64K0@0x3f00000 (the later means I
have tested 4-byte addressing).

Change-Id: I2117fc205006088967f3d97644375d10db1791f1
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-on: https://review.coreboot.org/26949
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/flashchips.h b/flashchips.h
index 4dce573..f4880d6 100644
--- a/flashchips.h
+++ b/flashchips.h
@@ -491,6 +491,7 @@
 #define MACRONIX_MX25U6435E	0x2537	/* Same as MX25U6435F */
 #define MACRONIX_MX25U12835E	0x2538	/* Same as MX25U12835F */
 #define MACRONIX_MX25U25635F	0x2539
+#define MACRONIX_MX25U51245G	0x253a
 #define MACRONIX_MX25L3235D	0x5E16	/* MX25L3225D/MX25L3235D/MX25L3237D */
 #define MACRONIX_MX25L6495F	0x9517