Add support for Macronix MX23L1654, MX23L6454 and MX23L12854 mask ROMs.

Signed-off-by: Michael Coppola <michael.n.coppola@gmail.com>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

git-svn-id: svn://flashrom.org/flashrom/trunk@1846 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1