HID: add feature_mapping callback

Currently hid doesn't export the features it knows to the specific modules.
Some information can be really important in such features: MosArt and
Cypress devices are by default not in a multitouch mode.
We have to send the value 2 on the right feature.

This patch exports to the module the features report so they can find the
right feature to set up the correct mode.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Acked-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>