logger: correctly format tv_usec

logger: correctly format tv_usec

tv_usec is an unspecified signed integer type.
The format string %u assumes an unsigned int, which is incorrect.
Especially on 32bit big-endian, where it can lead to invalid values.

Reported-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/util-linux/afef1b770ad80d50660bb2c53a0a8330b88d1049.camel@physik.fu-berlin.de/
Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
(cherry picked from commit 6227b2b0585ee2ccf224cf70c7144296a814a4ab)