pinctrl: baytrail: add warning for BYT_VAL_REG retrieval failure

Add warning for BYT_VAL_REG retrieval failure and continue such case
to avoid unintended reads/writes in pm_ops.

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20230616203356.27343-3-raag.jadav@intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Author: raagjadav

drivers/pinctrl/intel/pinctrl-baytrail.c

@@ -1758,6 +1758,10 @@ static int byt_gpio_suspend(struct device *dev)
 		vg->context.pads[i].conf0 = value;
 
 		reg = byt_gpio_reg(vg, pin, BYT_VAL_REG);
+		if (!reg) {
+			dev_warn(vg->dev, "Pin %i: can't retrieve VAL\n", i);
+			continue;
+		}
 		value = readl(reg) & BYT_VAL_RESTORE_MASK;
 		vg->context.pads[i].val = value;
 	}
@@ -1794,6 +1798,10 @@ static int byt_gpio_resume(struct device *dev)
 		}
 
 		reg = byt_gpio_reg(vg, pin, BYT_VAL_REG);
+		if (!reg) {
+			dev_warn(vg->dev, "Pin %i: can't retrieve VAL\n", i);
+			continue;
+		}
 		value = readl(reg);
 		if ((value & BYT_VAL_RESTORE_MASK) !=
 		     vg->context.pads[i].val) {