ACPI / TPM: fix memory leak when walking ACPI namespace

In function ppi_callback(), memory allocated by acpi_get_name() will get
leaked when current device isn't the desired TPM device, so fix the
memory leak.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/char/tpm/tpm_ppi.c

@@ -27,15 +27,18 @@ static char *tpm_device_name = "TPM";
 static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
 				void **return_value)
 {
-	acpi_status status;
+	acpi_status status = AE_OK;
 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
-	if (strstr(buffer.pointer, context) != NULL) {
-		*return_value = handle;
+
+	if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer))) {
+		if (strstr(buffer.pointer, context) != NULL) {
+			*return_value = handle;
+			status = AE_CTRL_TERMINATE;
+		}
 		kfree(buffer.pointer);
-		return AE_CTRL_TERMINATE;
 	}
-	return AE_OK;
+
+	return status;
 }
 
 static inline void ppi_assign_params(union acpi_object params[4],