xfs: skip zoned RT inodes in xfs_inodegc_want_queue_rt_file

The zoned allocator never performs speculative preallocations, so don't
bother queueing up zoned inodes here.

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