7241 Re-add removed protected method and mark it as deprecated

This is due to Backwards Compatibility reasons.

Author: avstudnitz

app/code/Magento/Customer/Model/Options.php

@@ -63,6 +63,18 @@ public function getNameSuffixOptions($store = null)
         );
     }
 
+    /**
+     * @param $options
+     * @param bool $isOptional
+     * @return array|bool
+     *
+     * @deprecated See prepareNamePrefixSuffixOptions
+     */
+    protected function _prepareNamePrefixSuffixOptions($options, $isOptional = false)
+    {
+        return $this->prepareNamePrefixSuffixOptions($options, $isOptional);
+    }
+
     /**
      * Unserialize and clear name prefix or suffix options
      * If field is optional, add an empty first option.