freevxfs: bmap: fix kernel-doc warnings

freevxfs: bmap: fix kernel-doc warnings

Fix -Wall kernel-doc warnings in vxfs_bmap.c:

vxfs_bmap.c:44: warning: Function parameter or member 'bn' not described in 'vxfs_bmap_ext4'
vxfs_bmap.c:44: warning: Excess function parameter 'iblock' description in 'vxfs_bmap_ext4'
vxfs_bmap.c:108: warning: No description found for return value of 'vxfs_bmap_indir'
vxfs_bmap.c:187: warning: No description found for return value of 'vxfs_bmap_typed'
vxfs_bmap.c:251: warning: No description found for return value of 'vxfs_bmap1'

Link: https://lkml.kernel.org/r/20231207212035.25345-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>