auto_assign_spans may be true even if not '1'

auto_assign_spans is an int and may have legal values other than 1. It
is legal (though pointless) to use: modprobe dahdi auto_assign_spans=3.
Any value != 0 is true.

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>
waitfor_xpds: handle the case of a failing AB

If an Astribank failed initialization, don't keep waiting for it.