ARM: dts: vf610-zii-dev: Wire up devel C switch interrupts

The devel B and devel C board use the same GPIO lines for interrupts
from the two switches. Move the pinmux nodes from devel B into the
shared .dtsi file, and wire up the interrupts on devel C.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>