ARM: imx: use __initconst for const init definition

0-DAY kernel build testing backend reports the following.

 scripts/checkpatch.pl 0001-ARM-imx-add-support-code-for-IMX50-based-machines.patch
 # many are suggestions rather than must-fix

 ERROR: Use of const init definition must use __initconst
 #80: arch/arm/mach-imx/mach-imx50.c:26:
 +static const char *imx50_dt_board_compat[] __initdata = {

While at it, fix the error globally for IMX platform.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/imx31-dt.c

@@ -25,7 +25,7 @@ static void __init imx31_dt_init(void)
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
-static const char *imx31_dt_board_compat[] __initdata = {
+static const char *imx31_dt_board_compat[] __initconst = {
 	"fsl,imx31",
 	NULL
 };

arch/arm/mach-imx/imx51-dt.c

@@ -29,7 +29,7 @@ static void __init imx51_dt_init(void)
 	platform_device_register_full(&devinfo);
 }
 
-static const char *imx51_dt_board_compat[] __initdata = {
+static const char *imx51_dt_board_compat[] __initconst = {
 	"fsl,imx51",
 	NULL
 };

arch/arm/mach-imx/mach-imx50.c

@@ -23,7 +23,7 @@ static void __init imx50_dt_init(void)
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
-static const char *imx50_dt_board_compat[] __initdata = {
+static const char *imx50_dt_board_compat[] __initconst = {
 	"fsl,imx50",
 	NULL
 };

arch/arm/mach-imx/mach-imx53.c

@@ -31,7 +31,7 @@ static void __init imx53_dt_init(void)
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
-static const char *imx53_dt_board_compat[] __initdata = {
+static const char *imx53_dt_board_compat[] __initconst = {
 	"fsl,imx53",
 	NULL
 };

arch/arm/mach-imx/mach-imx6q.c

@@ -273,7 +273,7 @@ static void __init imx6q_init_irq(void)
 	irqchip_init();
 }
 
-static const char *imx6q_dt_compat[] __initdata = {
+static const char *imx6q_dt_compat[] __initconst = {
 	"fsl,imx6dl",
 	"fsl,imx6q",
 	NULL,

arch/arm/mach-imx/mach-imx6sl.c

@@ -61,7 +61,7 @@ static void __init imx6sl_init_irq(void)
 	irqchip_init();
 }
 
-static const char *imx6sl_dt_compat[] __initdata = {
+static const char *imx6sl_dt_compat[] __initconst = {
 	"fsl,imx6sl",
 	NULL,
 };

arch/arm/mach-imx/mach-vf610.c

@@ -26,7 +26,7 @@ static void __init vf610_init_irq(void)
 	irqchip_init();
 }
 
-static const char *vf610_dt_compat[] __initdata = {
+static const char *vf610_dt_compat[] __initconst = {
 	"fsl,vf610",
 	NULL,
 };