intel-hid: fix volume buttons on Thinkpad X12 Detachable Tablet Gen 1

Volume buttons on Lenovo Thinkpad X12 Detachable Tablet Gen 1 did not
send any input events when pressed. When loading intel-hid with the 5
Button Array explicitly enabled, the buttons functioned normally.

Adds the X12 Detachable Tablet Gen 1 to the `button_array_table`.

However, the driver is unable to call INTEL_HID_DSM_BTNE_FN and prints
the warning "failed to set button capability" when attempting to enable
or disable the 5 Button Array. The warning should be harmless and
adding more special handling to avoid it is not worth it.

Co-developed-by: Mary Strodl <[e-mail]>
Signed-off-by: Mary Strodl <[e-mail]>
Signed-off-by: Cole Stowell <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Ilpo Järvinen <[e-mail]>
Signed-off-by: Ilpo Järvinen <[e-mail]>

drivers/platform/x86/intel/hid.c

···
 		},
 	},
 	{
+		.ident = "Lenovo ThinkPad X1 Tablet Gen 1",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X12 Detachable Gen 1"),
+		},
+	},
+	{
 		.ident = "Lenovo ThinkPad X1 Tablet Gen 2",
 		.matches = {
 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),