intel_th: Constify attribute_group structs

The only usage of them is to pass their address to sysfs_create_group()
and sysfs_remove_group(), both which have pointers to const
attribute_group structs as input. 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: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210414171251.14672-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/intel_th/intel_th.h

@@ -178,7 +178,7 @@ struct intel_th_driver {
 	/* file_operations for those who want a device node */
 	const struct file_operations *fops;
 	/* optional attributes */
-	struct attribute_group	*attr_group;
+	const struct attribute_group *attr_group;
 
 	/* source ops */
 	int			(*set_output)(struct intel_th_device *thdev,

drivers/hwtracing/intel_th/msu.c

@@ -2095,7 +2095,7 @@ static struct attribute *msc_output_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group msc_output_group = {
+static const struct attribute_group msc_output_group = {
 	.attrs	= msc_output_attrs,
 };
 

drivers/hwtracing/intel_th/pti.c

@@ -142,7 +142,7 @@ static struct attribute *pti_output_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group pti_output_group = {
+static const struct attribute_group pti_output_group = {
 	.attrs	= pti_output_attrs,
 };
 
@@ -295,7 +295,7 @@ static struct attribute *lpp_output_attrs[] = {
 	NULL,
 };
 
-static struct attribute_group lpp_output_group = {
+static const struct attribute_group lpp_output_group = {
 	.attrs	= lpp_output_attrs,
 };