Add no-canonical-prefixes to make sure paths in .d file are relative paths

Test: Ran "m out/soong/.intermediates/system/netd/bpf_progs/clatd.o/android_common/obj/system/netd/bpf_progs/clatd.o"
and verified that the output .d file did NOT contain absolute paths.

Change-Id: I2d187638eb7a6db8de057b83312cba3116985ac8
diff --git a/bpf/bpf.go b/bpf/bpf.go
index 59d1502..4cdfb31 100644
--- a/bpf/bpf.go
+++ b/bpf/bpf.go
@@ -60,6 +60,10 @@
 func (bpf *bpf) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	cflags := []string{
 		"-nostdlibinc",
+
+		// Make paths in deps files relative
+		"-no-canonical-prefixes",
+
 		"-O2",
 		"-isystem bionic/libc/include",
 		"-isystem bionic/libc/kernel/uapi",