pinctrl: pinconf: Fix display of configs

The function pinconf_dbg_config_print() only prints the configuration of
the 1st pin config in an array of pin configurations. Fix this so that
all pin configurations in the array are displayed.

There are a few places in the code where the pin configs are displayed
and so add a helper function to display the pin configs to simplify the
code.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>