generic/223: make sure all files get created on the data device

generic/223: make sure all files get created on the data device

This test formats filesystems with various stripe alignments, then
checks that data file allocations are actually aligned to those stripe
geometries.  If this test is run on an XFS filesystem with a realtime
volume and RTINHERIT is set on the root dir, the test will fail because
all new files will be created as realtime files, and realtime
allocations are not subject to data device stripe alignments.  Fix this
by clearing rtinherit on the root dir.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>