ftpd: add optional support for authentication

function                                             old     new   delta
cmdio_get_cmd_and_arg                                  -     237    +237
get_passwd                                             -      97     +97
check_password                                         -      82     +82
ftpd_main                                           2297    2178    -119
ask_and_check_password_extended                      206      84    -122
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 0/2 up/down: 416/-241)          Total: 175 bytes

Signed-off-by: Morten Kvistgaard <MK@pch-engineering.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/Config.src b/networking/Config.src
index fbad7ec..e566469 100644
--- a/networking/Config.src
+++ b/networking/Config.src
@@ -134,6 +134,13 @@
 	  it increases the code size by ~40 bytes.
 	  Most other ftp servers seem to behave similar to this.
 
+config FEATURE_FTP_AUTHENTICATION
+	bool "Enable authentication"
+	default y
+	depends on FTPD
+	help
+	  Enable basic system login as seen in telnet etc.
+
 config FTPGET
 	bool "ftpget"
 	default y