net: dsa: ar9331: constify struct regmap_bus

`ar9331_sw_bus` is not modified and can be declared as const to
move its data to a read-only section.

Signed-off-by: Javier Carrasco <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: javiercarrascocruz

drivers/net/dsa/qca/ar9331.c

@@ -1021,7 +1021,7 @@ static const struct regmap_config ar9331_mdio_regmap_config = {
 	.cache_type = REGCACHE_MAPLE,
 };
 
-static struct regmap_bus ar9331_sw_bus = {
+static const struct regmap_bus ar9331_sw_bus = {
 	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
 	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 	.read = ar9331_mdio_read,