soc: imx: gpc: fix PDN delay

imx6_pm_domain_power_off() reads iso and iso2sw from GPC_PGC_PUPSCR_OFFS
which stores the power up delays.
So use GPC_PGC_PDNSCR_OFFS for the correct delays.
Signed-off-by: Sven Schmitt <sven.schmitt@mixed-mode.de>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

drivers/soc/imx/gpc.c

@@ -69,7 +69,7 @@ static int imx6_pm_domain_power_off(struct generic_pm_domain *genpd)
 	u32 val;
 
 	/* Read ISO and ISO2SW power down delays */
-	regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val);
+	regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PDNSCR_OFFS, &val);
 	iso = val & 0x3f;
 	iso2sw = (val >> 8) & 0x3f;