Don't run the pre- and post-unregister hooks on a non-phone XPD
(practically: the echo canceller). This fixes a panic with manual
'dahdi_registertion off' as it is now called for the whole device
(regression of 2.6.x).
Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@10735 a0bf4364-ded3-4de4-8d8a-66a801d63aff