pinctrl: sunxi: Fix PIN_CONFIG_BIAS_PULL_{DOWN,UP} argument

According to pinconf-generic.h, the argument for
PIN_CONFIG_BIAS_PULL_{DOWN,UP} is non-zero if the bias is enabled
with a pull up/down resistor, zero if it is directly connected
to VDD or ground.

Since Allwinner hardware uses a weak pull resistor internally,
the argument should be 1.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>