Logs: put lower level for some logs

In fact, as they are often print together, they don't add
any value.

Author: GwendalRaoul

lib/platform/linux/serial.c

@@ -177,7 +177,7 @@ static ssize_t get_single_char(unsigned char * c, unsigned int timeout_ms)
         }
     } while (attempts-- > 0);
 
-    LOGW("Timeout to wait for char on serial line\n");
+    LOGD("Timeout to wait for char on serial line\n");
     return 0;
 }
 

lib/wpc/slip.c

@@ -253,7 +253,7 @@ int Slip_get_buffer(uint8_t * buffer, uint32_t len, uint16_t timeout_ms)
         res = read_function(&read, timeout_ms);
         if (res == 0)
         {
-            LOGW("Timeout to receive frame (size=%d)\n", size);
+            LOGD("Timeout to receive frame (size=%d)\n", size);
             return WPC_INT_TIMEOUT_ERROR;
         }
         else if (res < 0 || res > 1)

lib/wpc/wpc_internal.c

@@ -263,7 +263,7 @@ static int get_indication_locked(unsigned int max_ind, onIndicationReceivedLocke
     ret = send_request_locked(&request, &confirm, TIMEOUT_CONFIRM_MS);
     if (ret < 0)
     {
-        LOGE("Unable to poll for request\n");
+        LOGE("No poll answer\n");
         return ret;
     }