wpa_supplicant(hidl): Fix compilation failures

Changes:
1. libhidl uses c++14 bits, so remove the flag from Android.mk.
2. libhidl now supports hidl_array to/from std::array conversions. So,
use that.
3. libhidl does not expose the DeathRecipient class anymore. So, turn it
off untill the replacement is exposed.

Bug: 33397652
Test: Compiles after turning on CONFIG_CTRL_IFACE_HIDL=y.
Change-Id: Iedab05fc1b9cbb04cad06eb9f7a9e424d07b745e
4 files changed