iw: Fix timestamp output on 32-bit architectures

iw: Fix timestamp output on 32-bit architectures

On 32-bit architectures, time_t is 32-bit which causes overflows in the
arithmetic involving tv_sec, leading to invalid output. Fix this by
explicitly adding ULL suffixes to the constants used in those calculations.

Fixes: 3708f614dfdd ("iw: Print current time in station info dump")
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://lore.kernel.org/r/20210318224655.143489-1-toke@toke.dk
Signed-off-by: Johannes Berg <johannes.berg@intel.com>