Since FMT_timeval unconditionally uses %ld for both tv_sec and tv_usec,
and already casts tv_usec to long, also cast tv_sec to long.

Cc: Andreas Färber <afaerber@suse.de>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>