mtd: m25p80: Add support for Micron N25Q512A memory

Micron N25Q512A is a spi flash memory with following features:
-64MB size, 1.8V, Mulitple I/O, 4KB Sector erase memory.
-Memory is organised as 1024(64KB) main sectors.
-Each sector is divided into 256 pages.
-Register set/Opcodes are similar to other N25Q family products.

Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>