mtd: spi-nor: Add support for Micron n25q064a serial flash

Add Micron (n25q064a) 8MB flash to the list of supported chips.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
[Brian: fixup context]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>