xfs: remove metafile inodes from the active inode stat

xfs: remove metafile inodes from the active inode stat

The active inode (or active vnode until recently) stat can get much larger
than expected on file systems with a lot of metafile inodes like zoned
file systems on SMR hard disks with 10.000s of rtg rmap inodes.

Remove all metafile inodes from the active counter to make it more useful
to track actual workloads and add a separate counter for active metafile
inodes.

This fixes xfs/177 on SMR hard drives.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>