HID: hid-logitech: Collect report descriptors before sending

The current code allows several consecutive calls to hid_parse_report(),
which may have happened to work before, but would cause a memory leak
and generally be incorrect. This patch collects all the reports
before sending them once.

Cc: Nestor Lopez Casado <nlopezcasad@logitech.com>
Tested-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>