davinci: fix section mismatch warning in arch/arm/mach-davinci/board-dm646x-evm.c

A section mismatch is reported for gpio_led_platform_data
as it is referenced by a non annotated function (evm_led_setup)

This patch fixes the issue by converting the __initconst to const
as is the case in arch/arm/mach-davinci/board-dm644x-evm.c file.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/mach-davinci/board-dm646x-evm.c

@@ -194,7 +194,7 @@ static struct gpio_led evm_leds[] = {
 	{ .name = "DS4", .active_low = 1, },
 };
 
-static __initconst struct gpio_led_platform_data evm_led_data = {
+static const struct gpio_led_platform_data evm_led_data = {
 	.num_leds = ARRAY_SIZE(evm_leds),
 	.leds     = evm_leds,
 };