wifi(implementation): Dual interface support

Add support for concurrent interfaces in the WifiLegacyHal class:
a) Removed the hardcoded "wlan0" interface handle in WifiLegacyHal.
b) Modified all the interface specific functions to accept the |iface_name|
argument on which the operation needs to be performed.

Each IWifiIface object will hold the name of the underlying network
interface (wlan0, wlan1 or p2p0) which it is representing.
All IWifiChip operations which needs an iface name will continue to use
the default "wlan0".

Bug: 65671875
Test: Device boots up and connects to wifi networks.
Test: Will send for regression tests.
Change-Id: I9bd9c2a9ba33ac1ea5677fc5d7c261d8eac08e1d