frdm_k64f: Enable ftm driver instance and pins

If the ftm driver is enabled, use an instance routed to the Arduino
header and configure the pinmux accordingly. Unlike the hexiwear_k64,
the pins routed to the RGB led cannot be muxed as ftm channels.

Jira: ZEP-2025

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