xfs: fix scrub flagging rtinherit even if there is no rt device

xfs: fix scrub flagging rtinherit even if there is no rt device

BugLink: https://bugs.launchpad.net/bugs/1905618
[ Upstream commit c1f6b1ac00756a7108e5fcb849a2f8230c0b62a5 ]

The kernel has always allowed directories to have the rtinherit flag
set, even if there is no rt device, so this check is wrong.

Fixes: 80e4e1268802 ("xfs: scrub inodes")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>