HID: fix hid-ff drivers so that devices work even without ff support

Currently, the hid-*ff force feedback drivers, which claim the blacklisted
device on a HID bus, are only compiled in if the user selects force feedback
support.

However we want the device to be supported even when the kernel is configured
without force feedback.

This patch fixes the drivers in a way that they get compiled even if force
feedback is turned off; all the force feedback support code is compiled out in
such case, and the driver works as a usual driver on HID bus, claiming and
initializing the device, making it operational without FF effects.

Reported-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-zpff.c b/drivers/hid/hid-zpff.c
index 85a198a..57f71075 100644
--- a/drivers/hid/hid-zpff.c
+++ b/drivers/hid/hid-zpff.c
@@ -27,6 +27,7 @@
 
 #include "hid-ids.h"
 
+#ifdef CONFIG_ZEROPLUS_FF
 #include "usbhid/usbhid.h"
 
 struct zpff_device {
@@ -108,6 +109,12 @@
 
 	return 0;
 }
+#else
+static inline int zpff_init(struct hid_device *hid)
+{
+	return 0;
+}
+#endif
 
 static int zp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {