Fixed max length of MySql TEXT type declaration

This should be 65535 (2 ^ 16 - 1) in stead of 65532.
Modified docblock to show the max lengths.

lib/Doctrine/DBAL/Platforms/MySqlPlatform.php

@@ -193,17 +193,26 @@ class MySqlPlatform extends AbstractPlatform
     }
 
     /**
-     * {@inheritDoc}
+     * Gets the SQL snippet used to declare a CLOB column type.
+     *     TINYTEXT   : 2 ^  8 - 1 = 255
+     *     TEXT       : 2 ^ 16 - 1 = 65535
+     *     MEDIUMTEXT : 2 ^ 24 - 1 = 16777215
+     *     LONGTEXT   : 2 ^ 32 - 1 = 4294967295
+     *
+     * @param array $field
+     *
+     * @return string
      */
     public function getClobTypeDeclarationSQL(array $field)
     {
         if ( ! empty($field['length']) && is_numeric($field['length'])) {
             $length = $field['length'];
+
             if ($length <= 255) {
                 return 'TINYTEXT';
             }
 
-            if ($length <= 65532) {
+            if ($length <= 65535) {
                 return 'TEXT';
             }