Adding optional arg nw_gen into phone_setup_iwlan_for_subscription()

In order to consider WiFi Prefer + Flight Mode Off test case:
1. I add the optional arg nw_gen for
phone_setup_iwlan_for_subscription() to select 4G, 5G or nothing to do
based on test case requirement.
2. If nw_gen equals GEN_4G or GEN_5G, the function would call
ensure_network_generation_for_subscription() to select a specific RAT.

Bug: None
Test: Yes, locally
Change-Id: I908cd40e88536cff863d2fc03ec5d2671ace0e0f
1 file changed
tree: 687e7c52cd7487b3734a1b645e541b14c69adf46
  1. acts/
  2. acts_tests/
  3. tools/
  4. wts-acts/
  5. Android.mk
  6. OWNERS
  7. PREUPLOAD.cfg