platform/x86: hp-wmi: Fix error value for hp_wmi_tablet_state

hp_wmi_tablet_state() fails to return the correct error code when
hp_wmi_perform_query() returns the HP WMI query specific error code
that is a positive value.
Signed-off-by: NCarlo Caione <carlo@endlessm.com>
Signed-off-by: NDarren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/hp-wmi.c

@@ -290,7 +290,7 @@ static int hp_wmi_tablet_state(void)
 	int ret = hp_wmi_perform_query(HPWMI_HARDWARE_QUERY, 0, &state,
 				       sizeof(state), sizeof(state));
 	if (ret)
-		return ret;
+		return -EINVAL;
 
 	return (state & 0x4) ? 1 : 0;
 }