ARM: dts: vf610-zii-cfu1: Disable NOR flash/SPI controller

Only a certain number of CFU1's come with NOR flash populated. Disable
it by default to avoid trying to probe NOR flash on devices that don't
have it. Devices that do have it can rely on the bootloader to enable
this node.

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>