soc: sunxi: sram: Constify struct regmap_config

`sunxi_sram_regmap_config` is not modified and can be declared as const
to move its data to a read-only section.
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20240705-sunxi-sram-const-regmap_config-v1-1-1b997cd65d0f@gmail.comSigned-off-by: Chen-Yu Tsai <wens@csie.org>

drivers/soc/sunxi/sunxi_sram.c

@@ -344,7 +344,7 @@ static void sunxi_sram_unlock(void *_lock)
 	spin_unlock(lock);
 }
 
-static struct regmap_config sunxi_sram_regmap_config = {
+static const struct regmap_config sunxi_sram_regmap_config = {
 	.reg_bits       = 32,
 	.val_bits       = 32,
 	.reg_stride     = 4,