pinctrl: imx: Do not treat a PIN without MUX register as an error

BugLink: http://bugs.launchpad.net/bugs/1611833

commit ba562d5e upstream.

Some PINs do not have a MUX register, it is not an error.
It is necessary to allow the continuation of the PINs configuration,
otherwise the whole PIN-group will be configured incorrectly.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/pinctrl/freescale/pinctrl-imx.c

@@ -207,9 +207,9 @@ static int imx_pmx_set(struct pinctrl_dev *pctldev, unsigned selector,
 		pin_reg = &info->pin_regs[pin_id];
 
 		if (pin_reg->mux_reg == -1) {
-			dev_err(ipctl->dev, "Pin(%s) does not support mux function\n",
+			dev_dbg(ipctl->dev, "Pin(%s) does not support mux function\n",
 				info->pins[pin_id].name);
-			return -EINVAL;
+			continue;
 		}
 
 		if (info->flags & SHARE_MUX_CONF_REG) {