telnet: code shrink

telnet: code shrink

put_iac2(w,c) is mostly used with constants, fold them into one arg

function                                             old     new   delta
put_iac2_merged                                        -      46     +46
telnet_main                                         1603    1583     -20
con_escape                                           285     257     -28
put_iac2                                              50       -     -50
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/2 up/down: 46/-98)            Total: -52 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>