ARM: davinci: mark spi_board_info arrays as const

Building with LTO revealed that three spi_board_info arrays are marked
__initconst, but not const:

arch/arm/mach-davinci/board-dm365-evm.c: In function 'dm365_evm_init':
arch/arm/mach-davinci/board-dm365-evm.c:729:30: error: 'dm365_evm_spi_info' causes a section type conflict with 'dm646x_edma_device'
 static struct spi_board_info dm365_evm_spi_info[] __initconst = {
                              ^
arch/arm/mach-davinci/dm646x.c:603:42: note: 'dm646x_edma_device' was declared here
 static const struct platform_device_info dm646x_edma_device __initconst = {

This marks them const as well, as was originally intended.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-davinci/board-dm355-evm.c

@@ -368,7 +368,7 @@ static struct spi_eeprom at25640a = {
 	.flags		= EE_ADDR2,
 };
 
-static struct spi_board_info dm355_evm_spi_info[] __initconst = {
+static const struct spi_board_info dm355_evm_spi_info[] __initconst = {
 	{
 		.modalias	= "at25",
 		.platform_data	= &at25640a,

arch/arm/mach-davinci/board-dm355-leopard.c

@@ -217,7 +217,7 @@ static struct spi_eeprom at25640a = {
 	.flags		= EE_ADDR2,
 };
 
-static struct spi_board_info dm355_leopard_spi_info[] __initconst = {
+static const struct spi_board_info dm355_leopard_spi_info[] __initconst = {
 	{
 		.modalias	= "at25",
 		.platform_data	= &at25640a,

arch/arm/mach-davinci/board-dm365-evm.c

@@ -726,7 +726,7 @@ static struct spi_eeprom at25640 = {
 	.flags		= EE_ADDR2,
 };
 
-static struct spi_board_info dm365_evm_spi_info[] __initconst = {
+static const struct spi_board_info dm365_evm_spi_info[] __initconst = {
 	{
 		.modalias	= "at25",
 		.platform_data	= &at25640,