xfs/270: fix rocompat regex

xfs/270: fix rocompat regex

This test fails with the fsverity patchset because the rocompat feature
bit for verity is 0x10.  The regular expression used to check if the
output is hexadecimal requires a single-digit answer, which is no longer
the case.

Fixes: 5bb78c56ef ("xfs/270: Fix ro mount failure when nrext64 option is enabled")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>