Input: psmouse - allow disabing certain protocol extensions

Allow ALPS, LOGIPS2PP, LIFEBOOK, TRACKPOINT and TOUCHKIT protocol
extensions of psmouse to be disabled during compilation. This will
allow users save some memory when they are sure that they will only
use a certain type of mice.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/mouse/trackpoint.h b/drivers/input/mouse/trackpoint.h
index 050298b..c10a6e7 100644
--- a/drivers/input/mouse/trackpoint.h
+++ b/drivers/input/mouse/trackpoint.h
@@ -142,6 +142,13 @@
 	unsigned char ext_dev;
 };
 
-extern int trackpoint_detect(struct psmouse *psmouse, int set_properties);
+#ifdef CONFIG_MOUSE_PS2_TRACKPOINT
+int trackpoint_detect(struct psmouse *psmouse, int set_properties);
+#else
+inline int trackpoint_detect(struct psmouse *psmouse, int set_properties)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_MOUSE_PS2_TRACKPOINT */
 
 #endif /* _TRACKPOINT_H */