P2P: Disable 5GHz channels in 2.4 GHz only mode

When P2P device is configured in 2.4GHz only mode supplicant
should not advertize 5GHz channels in its go negotiation frames.
  Hence disable 5GHz band channels when 2.4 GHz band only mode
selected in Wi-Fi advanced settings.

Change-Id: Ice8c9de34b19587c7e8432842a79551cc0e2333a
CRs-Fixed: 682823

Conflicts:
	wifi/java/android/net/wifi/WifiNative.java