mfd: Replace strict_strtoul() with kstrtoul() in ab* and att*

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 37b7ce4c7..11656c2 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -2757,7 +2757,7 @@
 	unsigned int irq_index;
 	int err;
 
-	err = strict_strtoul(attr->attr.name, 0, &name);
+	err = kstrtoul(attr->attr.name, 0, &name);
 	if (err)
 		return err;