xfs: trace log reservations at mount time

At each mount, emit the transaction reservation type information via
tracepoints.  This makes it easier to compare the log reservation info
calculated by the kernel and xfsprogs so that we can more easily diagnose
minimum log size failures on freshly formatted filesystems.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>