platform/x86: dell-laptop: Add quirk entry for Latitude 7520

The Latitude 7520 supports AC timeouts, but it has no KBD_LED_AC_TOKEN
and so changes to stop_timeout appear to have no effect if the laptop
is plugged in.
Signed-off-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Acked-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20220426120827.12363-1-gabriele.mzt@gmail.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/dell/dell-laptop.c

@@ -80,6 +80,10 @@ static struct quirk_entry quirk_dell_inspiron_1012 = {
 	.kbd_led_not_present = true,
 };
 
+static struct quirk_entry quirk_dell_latitude_7520 = {
+	.kbd_missing_ac_tag = true,
+};
+
 static struct platform_driver platform_driver = {
 	.driver = {
 		.name = "dell-laptop",
@@ -336,6 +340,15 @@ static const struct dmi_system_id dell_quirks[] __initconst = {
 		},
 		.driver_data = &quirk_dell_inspiron_1012,
 	},
+	{
+		.callback = dmi_matched,
+		.ident = "Dell Latitude 7520",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude 7520"),
+		},
+		.driver_data = &quirk_dell_latitude_7520,
+	},
 	{ }
 };