wlan: Fix to handle the failure status on supplicant start.

WiFiController shall enter in to StaEnabledState state after the
request to start supplicant irrespective of status being success
or failure.Thus,any new attempts to turn on Wi-Fi later shall
fail as the controller statemachine is expected to be in
APStaDisabledState to start Wi-Fi.
Thus , start the supplicant on a command CMD_WIFI_TOGGLED in the
StaEnabledState if the current WiFi state is neither
WIFI_STATE_ENABLING nor WIFI_STATE_ENABLED.

Change-Id: If4c4913b608411bac334f9c201441aaf36d7675b
CRs-Fixed: 570305