mtd: spi-nor: macronix: Add support for mx25um51245g

commit 9254cf8fa83b457f13fe1d8b2282af4980d97dfa from
git@git.assembla.com:cavium/WindRiver.linux.git

The Macronix mx25um51245g is a 1.8V, 512 Mbit device.
It support x1 and x8(8-8-8 only) modes.

Change-Id: Iba1e040d6bbd26bf666fc59b68cc356f9107754b
Signed-off-by: Witold Sadowski <wsadowski@marvell.com>
Signed-off-by: Suneel Garapati <sgarapati@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/120908
Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Chandrakala Chavva <cchavva@marvell.com>
[RQ: fix build issue.]
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>