ARM: dts: cygnus: fix naming of pinctrl node

Remove 0x from pinctrl node to match device tree naming convention.

Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>