rtc: rtc-hid-sensor-time: add support for milliseconds

rtc: rtc-hid-sensor-time: add support for milliseconds

If a device sends milliseconds too, the driver will use them if it sets
the system clock at startup (through module option hctosys).

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>