[snmp] revert to default lib

thirdparty/lwip/src/apps/snmp/snmp_mib2_system.c

@@ -41,8 +41,6 @@
 #include "lwip/apps/snmp_scalar.h"
 #include "lwip/sys.h"
 
-#include "control_symbol.h"
-
 #include <string.h>
 
 #if LWIP_SNMP && SNMP_LWIP_MIB2
@@ -311,11 +309,11 @@ system_set_test(const struct snmp_scalar_array_node_def *node, u16_t len, void *
   if (*var_bufsize > 0) {
     if (var_wr_len == NULL) {
       /* we have to take the terminating 0 into account */
-      if (len < *var_bufsize && control_string_en_digit(value, len)) {
+      if (len < *var_bufsize) {
         ret = SNMP_ERR_NOERROR;
       }
     } else {
-      if (len <= *var_bufsize && control_string_en_digit(value, len)) {
+      if (len <= *var_bufsize) {
         ret = SNMP_ERR_NOERROR;
       }
     }