Summary:
- This commit makes nsh_telnetmain() in public so that we can
call it from applications.
- Also, CONFIG_NSH_DISABLE_TELNETSTART is introduced so that
we can disable nsh_telnetstart()
Impact:
- nsh with telnet daemon
Testing:
- Tested with sabre-6quad:netknsh (will be updated later)
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>