ACPI: Fix a warning of discarding qualifiers from pointer target type

drivers/acpi/ec.c: In function `acpi_ec_ecdt_probe':
drivers/acpi/ec.c:873: warning: passing arg 1 of `acpi_get_devices' discards qualifiers from pointer target type

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/namespace/nsxfeval.c

@@ -540,7 +540,7 @@ acpi_ns_get_device_callback(acpi_handle obj_handle,
  ******************************************************************************/
 
 acpi_status
-acpi_get_devices(char *HID,
+acpi_get_devices(const char *HID,
 		 acpi_walk_callback user_function,
 		 void *context, void **return_value)
 {

include/acpi/acpixf.h

@@ -130,7 +130,7 @@ acpi_walk_namespace(acpi_object_type type,
 		    void *context, void **return_value);
 
 acpi_status
-acpi_get_devices(char *HID,
+acpi_get_devices(const char *HID,
 		 acpi_walk_callback user_function,
 		 void *context, void **return_value);
 

include/acpi/acstruct.h

@@ -146,7 +146,7 @@ struct acpi_init_walk_info {
 struct acpi_get_devices_info {
 	acpi_walk_callback user_function;
 	void *context;
-	char *hid;
+	const char *hid;
 };
 
 union acpi_aml_operands {