Introduce & use FASTCONVERTFUNC with full prototype

modules/database/src/ioc/dbStatic/link.h

@@ -77,14 +77,14 @@ struct macro_link {
     char *macroStr;
 };
 
-struct dbCommon;
-typedef long (*LINKCVT)();
+struct dbAddr;
+typedef long (*FASTCONVERTFUNC)(const void *from, void *to, const struct dbAddr *paddr);
 
 struct pv_link {
     ELLNODE     backlinknode;
     char        *pvname;        /* pvname link points to */
     void        *pvt;           /* CA or DB private */
-    LINKCVT     getCvt;         /* input conversion function */
+    FASTCONVERTFUNC getCvt;     /* input conversion function */
     short       pvlMask;        /* Options mask */
     short       lastGetdbrType; /* last dbrType for DB or CA get */
 };