ddr: socfpga: gen5: constify altera_gen5_sdram_ops

Make the function pointer struct const, as it does not need to be
writable. This doesn't really change anything other than moving this
variable to a different section. No functional change.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>
diff --git a/drivers/ddr/altera/sdram_gen5.c b/drivers/ddr/altera/sdram_gen5.c
index fcd89b6..8c8ea19 100644
--- a/drivers/ddr/altera/sdram_gen5.c
+++ b/drivers/ddr/altera/sdram_gen5.c
@@ -626,7 +626,7 @@
 	return 0;
 }
 
-static struct ram_ops altera_gen5_sdram_ops = {
+static const struct ram_ops altera_gen5_sdram_ops = {
 	.get_info = altera_gen5_sdram_get_info,
 };