gn2bp: Drop upstream boringssl build rules in favor of local Android.bp am: 170dc8e82c

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2469601

Change-Id: Ib535ad4cda50a4acb1cb3cc1b3d4409eef538354
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>