Fix BPF_FD_JUST_USE_INT macro am: 26ca77305d

Original change: https://android-review.googlesource.com/c/platform/system/bpf/+/1512866

Change-Id: I0d6517ac29c60c91de8f05c5c26904915165a971
diff --git a/libbpf_android/include/bpf/BpfUtils.h b/libbpf_android/include/bpf/BpfUtils.h
index 428606a..310a889 100644
--- a/libbpf_android/include/bpf/BpfUtils.h
+++ b/libbpf_android/include/bpf/BpfUtils.h
@@ -29,7 +29,7 @@
 
 #ifdef BPF_FD_JUST_USE_INT
   #define BPF_FD_TYPE int
-  #define BPF_FD_TO_INT(x) (x)
+  #define BPF_FD_TO_INT(x) static_cast<__u32>(x)
 #else
   #include <android-base/unique_fd.h>
   #define BPF_FD_TYPE base::unique_fd&