bpf: annotate bpf_insn_print_t with __printf

Functions of type bpf_insn_print_t take printf-like format
string, mark the type accordingly.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NQuentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

kernel/bpf/disasm.h

@@ -29,8 +29,8 @@ extern const char *const bpf_class_string[8];
 
 const char *func_id_name(int id);
 
-typedef void (*bpf_insn_print_t)(struct bpf_verifier_env *env,
-				 const char *, ...);
+typedef __printf(2, 3) void (*bpf_insn_print_t)(struct bpf_verifier_env *env,
+						const char *, ...);
 typedef const char *(*bpf_insn_revmap_call_t)(void *private_data,
 					      const struct bpf_insn *insn);
 typedef const char *(*bpf_insn_print_imm_t)(void *private_data,