iio: Add Usage IDs for HID time sensors.

These are Usage IDs for the attributes year, month, day,
hour, minute and second, needed to read HID time sensors.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>