boards: arm: Add arduino header to all frdm boards

Adds a device tree nexus node to define which gpio pins are mapped from
the soc to the arduino header.

The frdm_kw41z board excludes the arduino A0 pin because it cannot be
muxed as a gpio on the soc.

Signed-off-by: Maureen Helm <maureen.helm@nxp.com>