xfs: consolidate realtime allocation arguments

xfs: consolidate realtime allocation arguments

Source kernel commit: 41f33d82cfd310e344fc9183f02cc9e0d2d27663

Consolidate the arguments passed around the rt allocator into a
struct xfs_rtalloc_arg similar to how the btree allocator arguments
are consolidated in a struct xfs_alloc_arg....

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