wpa_supplicant(hidl): Support add/remove interfaces

Add HIDL API's for adding/removing interfaces dynamically.
These interface params are pixel specific, so other OEM's will need to
modify the params to suit their device configuration.

Bug: 65673678
Test: VTS tests
Change-Id: I41d3452652bb2e2139aad4670b71c07fab4c574d
2 files changed