Input: unified force feedback support for memoryless devices

Consolidate core implementing memoryless devices in one module; added
support for gain and envelopes and periodic => rumble conversion.

Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/include/linux/input.h b/include/linux/input.h
index 81c6ea5..d8b0c56 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -1169,5 +1169,8 @@
 int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, struct file *file);
 int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file);
 
+int input_ff_create_memless(struct input_dev *dev, void *data,
+		int (*play_effect)(struct input_dev *, void *, struct ff_effect *));
+
 #endif
 #endif