Fixes for Async Soft Channel input device support

The add_record() routine wasn't properly checking for unsupported
link types, resulting in an assertion failure on IOC exit if the
record was left in a "bad" state.

modules/database/src/std/dev/devBiSoftCallback.c

@@ -79,7 +79,7 @@ static long add_record(dbCommon *pcommon)
     devPvt *pdevPvt;
     processNotify *ppn;
 
-    if (dbLinkIsDefined(plink) && dbLinkIsConstant(plink))
+    if (plink->type == CONSTANT)
         return 0;
 
     if (plink->type != PV_LINK) {