Changes

sccp_user: Fix ASP not restarted after associating a new AS to it

Recent commit introduced a regression when applying
default_layer_manager to all ASPs in m3ua-mode ASP.
The call to osmo_ss7_asp_restart() was moved to an inner code path but
I failed to figure out the ASP restart is also needed in this code path.

Fixes: ce63d3b2027cefb8412179497100d14ed3fee0dd
Change-Id: I5cccad3347dbea33433028e17571b1c16ecaf719