touchpad: Add a tp_post_pointer_motion helper function

Split out the pointer-motion handling into a helper function.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
touchpad: When a clickpad is clicked post combined motion of all touches

When clicking a clickpad the user may want to switch fingers to move the
pointer around, without lifting so as to not release the button.

Switch to using combined motion of all touches when a clickpad is clicked to
allow this.

BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=86807
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
touchpad: Use TOUCHPAD_MIN_SAMPLES in tp_get_delta

Use TOUCHPAD_MIN_SAMPLES in tp_get_delta rather then hardcoding "4".

Also remove the superfluous TOUCHPAD_MIN_SAMPLES check before calling
tp_get_delta in tp_get_pointer_delta, this is not necessary as tp_get_delta
already checks itself.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>