afsmonitor: Skip additional bits for large timeval

afsmonitor: Skip additional bits for large timeval

When the timeval structure uses 64-bit values for sec and usec,
64 extra bits need to be skipped in the input for every time value
that is parsed.  There's a remaining assumption in this part of the
code that the time values received from the server are 32-bits, but
after decoding they will always have the local size which may well
be 64-bits.

Change-Id: Iaf52df8f9da1146807dddc1c44a9e52e83654d9c
Reviewed-on: http://gerrit.openafs.org/10592
Reviewed-by: Daria Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>