wificond: Bug fix for parsing radio chain info

The signal strength (RSSI) field is stored as a list of
uint8_t attributes in the kernel.

Bug: 68335251
Test: Ensured radio chain info is present on crosshatch scan results.
Test: ./system/connectivity/wificond/runtests.sh
Change-Id: Ic11fca82e78d066ad0bf18fabad5162b5a834b81
3 files changed