Include bpf program in APEXes

bpf program is put to an APEX via 'bpfs' property. It is
placed under etc/bpf directory in it.

Fix: 167530625
Test: m

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/1418308

Merged-In: Ia36b486f0cffb619ecc4f7a318cde881abc5baf4
Change-Id: I42631beea4e668d86ba437d3e2edb392137706f0
(cherry picked from commit 05e47c0c5d2795687e5681febc6ff52b49d313be)
diff --git a/apex/Android.bp b/apex/Android.bp
index 144f441..1a5f683 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -5,6 +5,7 @@
         "blueprint",
         "soong",
         "soong-android",
+        "soong-bpf",
         "soong-cc",
         "soong-java",
         "soong-python",