5042 stop using deprecated atomic functions

@@ -372,11 +372,11 @@
 void
 fm_panic(const char *format, ...)
 {
         va_list ap;
 
-        (void) casptr((void *)&fm_panicstr, NULL, (void *)format);
+        (void) atomic_cas_ptr((void *)&fm_panicstr, NULL, (void *)format);
 #if defined(__i386) || defined(__amd64)
         fastreboot_disable_highpil();
 #endif /* __i386 || __amd64 */
         va_start(ap, format);
         vpanic(format, ap);