Logging in series of examples has misuse of "%d" instead of type-appropriate format specifiers.
Fix by changing "%d" to PRIxx macros corresponding to type.
Remove -Wno-format compile flag in those examples that are affected.
The ethernet\iperf example has a bug, once bandwidth is more than 80 Mbits/s the average counter shows wrong total transmitted data value. Issue occur due to overflow of the uint32_t total_len variable.
* created new average formula to avoid the overflow
* updated interval formula according to new variables
* renamed variable according to its purpose
