rockchip: rk3399: fix missing braces in full pinctrl

Braces around the error-case for rk3399_pinctrl_set_pin_pupd lead to
an unconditional (and unintended) return from the function without it
ever setting pin-configurations.

Fix it.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>