Input: psmouse - clean up Cypress probe

When Cypress protocol support is disabled cypress_init() is a stub that
always returns -ENOSYS, so there is not point in testing for
CONFIG_MOUSE_PS2_CYPRESS after we decided that we are dealing with a
Cypress device. Also, we should only be calling cypress_detect() when
set_properties argument is "true", like with other protocols.

There is a slight change in behavior to make follow-up patches more
uniform: when we detect Cypress but its initialization fails, instead of
immediately returning PSMOUSE_PS2 protocol we now continue trying
IntelliMouse [Explorer]. Given that Cypress devices only have issue with
Sentelic probes probing Imtellimouse should be safe.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Marcin Sochacki <msochacki+kernel@gmail.com>
Tested-by: Till <till2.schaefer@uni-dortmund.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/psmouse-base.c

@@ -836,9 +836,8 @@ static int psmouse_extensions(struct psmouse *psmouse,
 	 * Trackpads.
 	 */
 	if (max_proto > PSMOUSE_IMEX &&
-			cypress_detect(psmouse, set_properties) == 0) {
-		if (IS_ENABLED(CONFIG_MOUSE_PS2_CYPRESS)) {
-			if (cypress_init(psmouse) == 0)
+	    psmouse_do_detect(cypress_detect, psmouse, set_properties) == 0) {
+		if (!set_properties || cypress_init(psmouse) == 0)
 			return PSMOUSE_CYPRESS;
 
 		/*
@@ -846,9 +845,6 @@ static int psmouse_extensions(struct psmouse *psmouse,
 		 * Cypress Trackpad, must avoid Finger Sensing Pad
 		 * probe if Cypress Trackpad device detected.
 		 */
-			return PSMOUSE_PS2;
-		}
-
 		max_proto = PSMOUSE_IMEX;
 	}