platform/x86: lg-laptop: Use correct event for touchpad toggle FN-key

Send F21 which is the standard for this key, instead of F13.
Signed-off-by: Matan Ziv-Av <matan@svgalib.org>
Link: https://lore.kernel.org/r/b847895c1f170e2e59df5757a4d603d28149f648.1629291912.git.matan@svgalib.orgReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Documentation/admin-guide/laptops/lg-laptop.rst

@@ -13,7 +13,7 @@ Hotkeys
 The following FN keys are ignored by the kernel without this driver:
 
 - FN-F1 (LG control panel)   - Generates F15
-- FN-F5 (Touchpad toggle)    - Generates F13
+- FN-F5 (Touchpad toggle)    - Generates F21
 - FN-F6 (Airplane mode)      - Generates RFKILL
 - FN-F8 (Keyboard backlight) - Generates F16.
   This key also changes keyboard backlight mode.

drivers/platform/x86/lg-laptop.c

@@ -74,7 +74,7 @@ static int battery_limit_use_wmbb;
 
 static const struct key_entry wmi_keymap[] = {
 	{KE_KEY, 0x70, {KEY_F15} },	 /* LG control panel (F1) */
-	{KE_KEY, 0x74, {KEY_F13} },	 /* Touchpad toggle (F5) */
+	{KE_KEY, 0x74, {KEY_F21} },	 /* Touchpad toggle (F5) */
 	{KE_KEY, 0xf020000, {KEY_F14} }, /* Read mode (F9) */
 	{KE_KEY, 0x10000000, {KEY_F16} },/* Keyboard backlight (F8) - pressing
 					  * this key both sends an event and