libmsc/gsm_09_11.c: do not abuse LOG_TRANS() in gsm0911_rcv_nc_ss()

If we 100% sure that trans == NULL, it makes more sense to use
generic LOGP(DSS, LOGL_*, ...) call, so the logs can reflect
more information than such dummy prefix:

  trans(NULL NULL callref-0x0 tid-0) ...

Change-Id: I6b68a0f0b32eb126e0f7e914a314130254d28467
1 file changed