pinctrl: imx: fix NO_PAD_CTL setting for MMIO pads

After patch b96eea71 ("pinctrl: fsl: add scu based pinctrl support"),
NO_PAD_CTL pads map are not skipped anymore which results in
a possible memory corruption. As we actually only need to create config
maps for SCU pads and MMIO pads which are not using the default config
(a.k.a IMX_NO_PAD_CTL), so let's add a proper check before creating
the config maps. And during MMIO pads parsing, we also need update the
list_p point as SCU case to ensure the pin data next parsed is correct.

Cc: Linus Walleij <linus.walleij@linaro.org>
Fixes: b96eea71 ("pinctrl: fsl: add scu based pinctrl support")
Reported-by: Martin Kaiser <martin@kaiser.cx>
Suggested-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Leonard Crestez <leonard.crestez@nxp.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>