pinctrl: nomadik: improve GPIO debug prints

The debugfs file would only define if the line was "pulled" and
not which direction (pull up or pull down). Improve this by
taking two print paths depending on whether the pin is set as
input or output and use the data register directly to figure
out whether the pin is set for pull up or pull down.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>