arm: socfpga: make config structs const

There are two config structs left in wrap_sdram_config.c that can
be made const.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
diff --git a/arch/arm/mach-socfpga/wrap_sdram_config.c b/arch/arm/mach-socfpga/wrap_sdram_config.c
index 8cfacc7..2b072cc 100644
--- a/arch/arm/mach-socfpga/wrap_sdram_config.c
+++ b/arch/arm/mach-socfpga/wrap_sdram_config.c
@@ -251,7 +251,7 @@
 		RW_MGR_MEM_VIRTUAL_GROUPS_PER_WRITE_DQS,
 };
 
-struct socfpga_sdram_io_config io_config = {
+static const struct socfpga_sdram_io_config io_config = {
 	.delay_per_dchain_tap		= IO_DELAY_PER_DCHAIN_TAP,
 	.delay_per_dqs_en_dchain_tap	= IO_DELAY_PER_DQS_EN_DCHAIN_TAP,
 	.delay_per_opa_tap		= IO_DELAY_PER_OPA_TAP,
@@ -269,7 +269,7 @@
 	.shift_dqs_en_when_shift_dqs	= IO_SHIFT_DQS_EN_WHEN_SHIFT_DQS,
 };
 
-struct socfpga_sdram_misc_config misc_config = {
+static const struct socfpga_sdram_misc_config misc_config = {
 	.afi_rate_ratio			= AFI_RATE_RATIO,
 	.calib_lfifo_offset		= CALIB_LFIFO_OFFSET,
 	.calib_vfifo_offset		= CALIB_VFIFO_OFFSET,