ACPI / scan: constify first argument of struct acpi_scan_handler::match

One wouldn't expect a "match" function modify the string it searches
for, and indeed the only instance of the struct
acpi_scan_handler::match callback, acpi_pnp_match, can easily be
changed. While there, update its helper matching_id().

This is also preparation for constifying struct acpi_hardware_id::id.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_pnp.c

@@ -316,7 +316,7 @@ static const struct acpi_device_id acpi_pnp_device_ids[] = {
 	{""},
 };
 
-static bool matching_id(char *idstr, char *list_id)
+static bool matching_id(const char *idstr, const char *list_id)
 {
 	int i;
 
@@ -333,7 +333,7 @@ static bool matching_id(char *idstr, char *list_id)
 	return true;
 }
 
-static bool acpi_pnp_match(char *idstr, const struct acpi_device_id **matchid)
+static bool acpi_pnp_match(const char *idstr, const struct acpi_device_id **matchid)
 {
 	const struct acpi_device_id *devid;
 

include/acpi/acpi_bus.h

@@ -129,7 +129,7 @@ static inline struct acpi_hotplug_profile *to_acpi_hotplug_profile(
 struct acpi_scan_handler {
 	const struct acpi_device_id *ids;
 	struct list_head list_node;
-	bool (*match)(char *idstr, const struct acpi_device_id **matchid);
+	bool (*match)(const char *idstr, const struct acpi_device_id **matchid);
 	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
 	void (*detach)(struct acpi_device *dev);
 	void (*bind)(struct device *phys_dev);