USB: usbmon: Use 64bit timestamp for mon_bin_hdr

struct mon_bin_hdr allows for a 64-bit seconds timestamp. The code
currently uses 'struct timeval' to populate the timestamp in mon_bin_hdr,
which has a 32-bit seconds field and will overflow in year 2038 and beyond.
This patch replaces 'struct timeval' with 'struct timespec64' which is
y2038 safe. This patch is part of a larger attempt to remove instances
of struct timeval and other 32-bit timekeeping (time_t, struct timespec)
from the kernel.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>