syslogd: do not need to poll(), we can just block in read().

syslogd: do not need to poll(), we can just block in read().

function                                             old     new   delta
syslogd_main                                        1206    1106    -100
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-100)           Total: -100 bytes
   text    data     bss     dec     hex filename
 769820    1051   10764  781635   bed43 busybox_old
 769702    1051   10764  781517   beccd busybox_unstripped