Move the pinmux setting of the EP93xx GPIOs to the core code. This removes the need for the GPIO driver to have access to the system controller registers. Signed-off-by: Ryan Mallon <rmallon@gmail.com> Cc: Grant Likely <grant.likely@secretlab.ca> Reviewed-by: Mika Westerberg <mika.westerberg@iki.fi> Acked-by: Hartley Sweeten <hsweeten@visionengravers.com>