BPF: remove duplicate cflags and update btf flags.

With the addition of the -Wall, -Werror, -Wextra cflags to the bpf soong
module as default, they are no longer necessary in the bpf definition in
Android.bp files.

Additionally, 'btf: true'  is now set by default by the build system. To counter this and maintain the existing behavior, add 'btf: false' where necessary.

Test: treehugger
Change-Id: Ic5029319e82a45cdbfa6c5f4c4375dab7fea7284
Signed-off-by: Neill Kapron <nkapron@google.com>

Author: nkapron

services/gpuservice/bpfprogs/Android.bp

@@ -24,9 +24,4 @@ package {
 bpf {
     name: "gpuMem.o",
     srcs: ["gpuMem.c"],
-    btf: true,
-    cflags: [
-        "-Wall",
-        "-Werror",
-    ],
 }

services/gpuservice/gpuwork/bpfprogs/Android.bp

@@ -19,12 +19,10 @@ package {
 bpf {
     name: "gpuWork.o",
     srcs: ["gpuWork.c"],
+    // Without btf disabled, presubmits will fail.
+    btf: false,
     cflags: [
-        "-Wall",
-        "-Werror",
-        "-Wformat",
         "-Wthread-safety",
-        "-Wunused",
         "-Wunreachable-code",
     ],
 }