Eliminate some compilation warnings.

Author: deyouslamtec

sdk/src/arch/linux/net_socket.cpp

@@ -723,7 +723,7 @@ class _single_thread DGramSocketImpl : public DGramSocket
         assert(addr);
         size_t ans = ::sendto( _socket_fd, buffer, len, 0, addr, sizeof(sockaddr_storage));
         if (ans != (size_t)-1) {
-            assert(ans == (int)len);
+            assert(ans == len);
             return RESULT_OK;
         } else {
             switch (errno) {

sdk/src/sl_lidar_driver.cpp

@@ -175,7 +175,7 @@ namespace sl {
         if (i == count) return SL_RESULT_OPERATION_FAIL;
 
         //Tune tail
-        for (i = count - 1; i >= 0; i--) {
+        for (i = count - 1; i < count; i--) {
             if (getDistanceQ2(nodebuffer[i]) == 0) {
                 continue;
             }