xfs: Hoist xfs_attr_node_addname

xfs: Hoist xfs_attr_node_addname

Source kernel commit: 5d954cc09f6baed80458ea02ec092031608ea3fe

This patch hoists the later half of xfs_attr_node_addname into
the calling function.  We do this because it is this area that
will need the most state management, and we want to keep such
code in the same scope as much as possible

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>