Input: psmouse - use IS_ENABLED instead of homegrown code

Instead of having various protocols provide <protocol>_supported()
functions, let's use IS_ENABLED() macro that works well in "if" statements.

Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/cypress_ps2.h

@@ -172,7 +172,6 @@ struct cytp_data {
 #ifdef CONFIG_MOUSE_PS2_CYPRESS
 int cypress_detect(struct psmouse *psmouse, bool set_properties);
 int cypress_init(struct psmouse *psmouse);
-bool cypress_supported(void);
 #else
 inline int cypress_detect(struct psmouse *psmouse, bool set_properties)
 {
@@ -182,10 +181,6 @@ inline int cypress_init(struct psmouse *psmouse)
 {
 	return -ENOSYS;
 }
-inline bool cypress_supported(void)
-{
-	return 0;
-}
 #endif /* CONFIG_MOUSE_PS2_CYPRESS */
 
 #endif  /* _CYPRESS_PS2_H */