libbpf: Add __arg_arena to bpf_helpers.h

Add __arg_arena to bpf_helpers.h

Signed-off-by: Alexei Starovoitov <[e-mail]>
Signed-off-by: Andrii Nakryiko <[e-mail]>
Acked-by: Kumar Kartikeya Dwivedi <[e-mail]>
Acked-by: Andrii Nakryiko <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/lib/bpf/bpf_helpers.h

···
 #define __arg_nonnull __attribute((btf_decl_tag("arg:nonnull")))
 #define __arg_nullable __attribute((btf_decl_tag("arg:nullable")))
 #define __arg_trusted __attribute((btf_decl_tag("arg:trusted")))
+#define __arg_arena __attribute((btf_decl_tag("arg:arena")))
 
 #ifndef ___bpf_concat
 #define ___bpf_concat(a, b) a ## b