platform/chrome: Constify static attribute_group structs

The only usage of these is to print their name in a dev_err-message, and
to pass their address to sysfs_create_group() and sysfs_remove_group(),
both which takes pointers to const. Make them const to allow the compiler
to put them in read-only memory.
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210109001748.58036-1-rikard.falkeborn@gmail.com

drivers/platform/chrome/cros_ec_lightbar.c

@@ -523,7 +523,7 @@ static struct attribute *__lb_cmds_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group cros_ec_lightbar_attr_group = {
+static const struct attribute_group cros_ec_lightbar_attr_group = {
 	.name = "lightbar",
 	.attrs = __lb_cmds_attrs,
 };

drivers/platform/chrome/cros_ec_sysfs.c

@@ -329,7 +329,7 @@ static umode_t cros_ec_ctrl_visible(struct kobject *kobj,
 	return a->mode;
 }
 
-static struct attribute_group cros_ec_attr_group = {
+static const struct attribute_group cros_ec_attr_group = {
 	.attrs = __ec_attrs,
 	.is_visible = cros_ec_ctrl_visible,
 };

drivers/platform/chrome/cros_ec_vbc.c

@@ -101,7 +101,7 @@ static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
 	NULL
 };
 
-static struct attribute_group cros_ec_vbc_attr_group = {
+static const struct attribute_group cros_ec_vbc_attr_group = {
 	.name = "vbc",
 	.bin_attrs = cros_ec_vbc_bin_attrs,
 };

drivers/platform/chrome/wilco_ec/sysfs.c

@@ -236,7 +236,7 @@ static struct attribute *wilco_dev_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group wilco_dev_attr_group = {
+static const struct attribute_group wilco_dev_attr_group = {
 	.attrs = wilco_dev_attrs,
 };