ARM: dts: am335x-icev2: Add SPI based NOR

Enable support for W25Q64CVSSIG which is a Winbond 64 Mbit SPI NOR.

At boot you will see the following message:
m25p80 spi1.0: found s25fl064k, expected w25q64

This is because the JEDEC ID for this chip is the same as s25fl064k.
However, this should be harmless since both chips are essentially the
same.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>