syslog: syslog_device ops are handled internally by the driver.

include/nuttx/syslog/syslog.h

@@ -101,9 +101,7 @@ struct syslog_channel_ops_s
   syslog_putc_t  sc_putc;   /* Normal buffered output */
   syslog_putc_t  sc_force;  /* Low-level output for interrupt handlers */
   syslog_flush_t sc_flush;  /* Flush buffered output (on crash) */
-#ifdef CONFIG_SYSLOG_WRITE
   syslog_write_t sc_write;  /* Write multiple bytes */
-#endif
 };
 
 /* This structure provides the interface to a SYSLOG channel */