HID: logitech-hidpp: handle battery events in hidpp_raw_hidpp_event()

Battery events are reported through HID++, so we need to be sure
the report ID is the HID++ one.

Without this, we might receive keyboard events that looks just like
battery events with wrong data and which will confuse user space.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>