ARM: dts: vf610-zii-dev: Add QSPI node

Both rev C and rev B of the board come with two QSPI-NOR chips
attached to the SoC. Add DT code describing all of this.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Shawn Guo <shawnguo@kernel.org>