HID: only dump report traffic with debug level 2

Currently using debug=1 with hid module prints out all sent and received
reports to the kernel log, while in many cases we only want to see the
report descriptors and hid-input mappings that are printed when a device
is probed.

Add new level debug=2, and only dump the report traffic with that level.

Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>