[SL-UP][WiFi] Fixing the rssi value for wf200

[chirag-silabs]

WF200 scan was sending RCPI value rather than the RSSI value. Fixing it so that the send value is RSSI

Formula for the RSSI

The following equation can be used to convert the RCPI value to corresponding dBm value.
[signal level in dBm] = (RCPI / 2) - 110

https://docs.silabs.com/wifi/wf200/rtos/latest/group-w-f-m-g-r-o-u-p-c-o-n-c-e-p-t-s

Tested on WF200

[mkardous-silabs]

RSSI is calculated in two different locations. The fix should be donne in both location.

[chirag-silabs]

RSSI is calculated in two different locations. The fix should be donne in both location.

The calution was correct at the other place, anyhow made it similar to match the formula

[mkardous-silabs]

@chirag-silabs I would suggest having an inline function that does the calcluation instead of implementing the calculation twice.

function takes the rcpi and returns rssi.