The do_gettimeofday() helper was removed by commit e4b92b108c6c
("timekeeping: remove obsolete time accessors") in v5.0-rc1. Bring it back
for users in vmmon-only/linux/hostif.c.
This feels like a quick and clumsy band aid to allow build with post-4.20
kernels. On a closer look, the whole gymnastics around uptimeState and
HostIFReadUptimeWork() with jiffies and wall time checking and correcting
each other seems to be a workaround for an absence of high resolution
monotonic time. Considering ktime_get_ts64() is available since 3.17 and
before that, ktime_get_ts() since 2.6.17, perhaps the time has come to
clean all this machinery up. But something like this would be beyond the
scope of this repository.