Changes

sccp_user: Fix dynamic ASP not associated to AS

Recent commit introduced a regression when applying
default_layer_manager to all ASPs in m3ua-mode ASP.
The call to osmo_ss7_as_add_asp() was moved to an inner code path but
forgot to add it in another code path.

Fixes: ce63d3b2027cefb8412179497100d14ed3fee0dd
Change-Id: I16371ef813c2e12993caae16a1626d10ae8ded54