ACPI / scan: Fix memory leak on acpi_scan_init_hotplug() error path

Following commit 6b772e8f (ACPI: Update PNPID match handling for
notify), the acpi_scan_init_hotplug() calls acpi_set_pnp_ids() which
allocates acpi_hardware_id and copies a few strings (kstrdup). If the
devices does not have hardware_id set, the function exits without
freeing the previously allocated ids (and kmemleak complains). This
patch calls simply changes 'return' on error to a 'goto out' which
calls acpi_free_pnp_ids().
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/scan.c

@@ -1785,7 +1785,7 @@ static void acpi_scan_init_hotplug(acpi_handle handle, int type)
 	acpi_set_pnp_ids(handle, &pnp, type);
 
 	if (!pnp.type.hardware_id)
-		return;
+		goto out;
 
 	/*
 	 * This relies on the fact that acpi_install_notify_handler() will not
@@ -1800,6 +1800,7 @@ static void acpi_scan_init_hotplug(acpi_handle handle, int type)
 		}
 	}
 
+out:
 	acpi_free_pnp_ids(&pnp);
 }