ARM: shmobile: emev2: Use __initconst for const init definition

__initconst must be used instead of __initdata for
const init definitions.

This problem was introduced by 3d5de27174955702 ("mach-shmobile: Emma
Mobile EV2 DT support V3") in v3.4-rc7.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/setup-emev2.c

@@ -58,7 +58,7 @@ static void __init emev2_add_standard_devices_dt(void)
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
-static const char *emev2_boards_compat_dt[] __initdata = {
+static const char *emev2_boards_compat_dt[] __initconst = {
 	"renesas,emev2",
 	NULL,
 };