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: NRyan Mallon <rmallon@gmail.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: NMika Westerberg <mika.westerberg@iki.fi>
Acked-by: NHartley Sweeten <hsweeten@visionengravers.com>