soc: imx: gpc: use GPC_PGC_DOMAIN_* indexes

index 35cc1d2dc4d5..6618ff1eaebd 100644
@@ -247,6 +247,7 @@ builtin_platform_driver(imx_pgc_power_domain_driver)
 #define GPC_PGC_DOMAIN_ARM	0
 #define GPC_PGC_DOMAIN_PU	1
 #define GPC_PGC_DOMAIN_DISPLAY	2
+#define GPC_PGC_DOMAIN_PCI	3
 
 static struct genpd_power_state imx6_pm_domain_pu_state = {
 	.power_off_latency_ns = 25000,

@@ -254,12 +255,13 @@ static struct genpd_power_state imx6_pm_domain_pu_state = {
 };
 
 static struct imx_pm_domain imx_gpc_domains[] = {
-	{
+	[GPC_PGC_DOMAIN_ARM] {
 		.base = {
 			.name = "ARM",
 			.flags = GENPD_FLAG_ALWAYS_ON,
 		},
-	}, {
+	},
+	[GPC_PGC_DOMAIN_PU] {
 		.base = {
 			.name = "PU",
 			.power_off = imx6_pm_domain_power_off,

@@ -269,7 +271,8 @@ static struct imx_pm_domain imx_gpc_domains[] = {
 		},
 		.reg_offs = 0x260,
 		.cntr_pdn_bit = 0,
-	}, {
+	},
+	[GPC_PGC_DOMAIN_DISPLAY] {
 		.base = {
 			.name = "DISPLAY",
 			.power_off = imx6_pm_domain_power_off,

@@ -277,7 +280,8 @@ static struct imx_pm_domain imx_gpc_domains[] = {
 		},
 		.reg_offs = 0x240,
 		.cntr_pdn_bit = 4,
-	}, {
+	},
+	[GPC_PGC_DOMAIN_PCI] {
 		.base = {
 			.name = "PCI",
 			.power_off = imx6_pm_domain_power_off,

@@ -343,8 +347,8 @@ static const struct regmap_config imx_gpc_regmap_config = {
 };
 
 static struct generic_pm_domain *imx_gpc_onecell_domains[] = {
-	&imx_gpc_domains[0].base,
-	&imx_gpc_domains[1].base,
+	&imx_gpc_domains[GPC_PGC_DOMAIN_ARM].base,
+	&imx_gpc_domains[GPC_PGC_DOMAIN_PU].base,
 };
 
 static struct genpd_onecell_data imx_gpc_onecell_data = {