platform/x86: dell-wmi: clean up wmi descriptor check

Some cases the wrong type was used for errors and checks can be
done more cleanly.
Signed-off-by: NMario Limonciello <mario.limonciello@dell.com>
Reviewed-by: NEdward O'Callaghan <quasisec@google.com>
Suggested-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NPali Rohár <pali.rohar@gmail.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/dell-wmi.c

@@ -663,16 +663,16 @@ static int dell_wmi_check_descriptor_buffer(struct wmi_device *wdev)
 
 	buffer = (u32 *)obj->buffer.pointer;
 
-	if (buffer[0] != 0x4C4C4544 && buffer[1] != 0x494D5720) {
-		dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%*ph)\n",
-			8, buffer);
+	if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
+		dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
+			buffer);
 		ret = -EINVAL;
 		goto out;
 	}
 
 	if (buffer[2] != 0 && buffer[2] != 1)
-		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%d)\n",
-			buffer[2]);
+		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
+			(unsigned long) buffer[2]);
 
 	if (buffer[3] != 4096)
 		dev_warn(&wdev->dev, "Dell descriptor buffer has invalid buffer length (%d)\n",