Remove Javadoc 1.4+ / -1.1 switch related warning (#1240)

* Remove ignored -1.1 switch warning

* Add @deprecated reason to `old`, no longer used parameter

---------

Signed-off-by: Olivier Lamy <[email protected]>
Co-authored-by: Olivier Lamy <[email protected]>

Author: perceptron8

src/main/java/org/apache/maven/plugins/javadoc/AbstractJavadocMojo.java

@@ -733,6 +733,7 @@ public AbstractJavadocMojo(
      * Javadoc 1.1. This is no longer supported since Javadoc 1.4 (shipped with JDK 1.4)
      *
      * @see <a href="https://docs.oracle.com/javase/7/docs/technotes/tools/windows/javadoc.html#a1.1">Javadoc option 1.1</a>.
+     * @deprecated No longer used.
      */
     @Parameter(property = "old", defaultValue = "false")
     @Deprecated
@@ -4324,10 +4325,6 @@ private void addJavadocOptions(
 
         // all options in alphabetical order
 
-        if (getLog().isWarnEnabled()) {
-            getLog().warn("Javadoc 1.4+ doesn't support the -1.1 switch anymore. Ignore this option.");
-        }
-
         addArgIfNotEmpty(arguments, "-bootclasspath", JavadocUtil.quotedPathArgument(getBootclassPath()));
 
         if (breakiterator) {