Raw Throughput testing

This feature provides functionality to test throughput over required transport layer (SPI or SDIO).
When triggered by host, this will bypass Wi-Fi traffic and push the dummy data traffic on transport layer directly to check maximum throughput on the current transport.
This feature will also help you to check if transport layer is properly configured or not.

Steps to test Raw TP

Raw throughput feature is enabled by default for ESP firmware
On Host side:
1. While setting up the host, pass rawtp_host_to_esp or rawtp_esp_to_host as a argument to rpi_init.sh.
  - e.g if you are setting Wi-Fi over SDIO and you want to test raw TP from ESP to host over SDIO interface, then compile and load host driver as below:
```
$ cd esp_hosted_ng/host/
$ ./rpi_init.sh sdio rawtp_esp_to_host
```
2. RAW throught is enabled by default for host, to disable it set the value of TEST_RAW_TP to 0 in esp_hosted/esp_hosted_ng/host/include/stats.h