wifi: Support register/unregister SoftApCallback for Lohs

Add API definition only.

Bug: 171928468
CTS-Coverage-Bug: 197529327
Test: atest -c FrameworksWifiTests
Test: atest -c FrameworksWifiApiTests
Merged-In: I796f203127821c63ecea12495cdf871fb6d540b2
Change-Id: I3ecc4ac3907ca4bf1e1287ab6ea925bc49d65664
5 files changed