HID: core: lower log level for unknown main item tags to warnings

Given all the effort distros have done with splash-screens to give
users a nice clean boot experience, we really want dmesg --level=err
to not print anything unless there is a real problem with either the
hardware or the kernel. Buggy HID descriptors unfortunately happen
all too often, so lower the log level to warning keep the console
clear of error messages such as:

[  441.079664] apple 0005:05AC:0239.0003: unknown main item tag 0x0

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>