Input: hp_sdc - convert to ktime_get()

This gets rid of the deprecated do_gettimeofday() call in favor
of ktime_get(), which is also more reliable as it uses monotonic
times. The code now gets a bit simpler.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Patchwork-Id: 10076621
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>