libbpf: Fix another __u64 cast in printf

Another issue of __u64 needing either %lu or %llu, depending on the
architecture. Fix with cast to `unsigned long long`.

Fixes: 7e06aad5 ("libbpf: Add multi-prog section support for struct_ops")
Signed-off-by: NAndrii Nakryiko <andriin@fb.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200904041611.1695163-1-andriin@fb.com

tools/lib/bpf/libbpf.c

@@ -8224,7 +8224,7 @@ static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
 		}
 		if (sym.st_value % BPF_INSN_SZ) {
 			pr_warn("struct_ops reloc %s: invalid target program offset %llu\n",
-				map->name, (__u64)sym.st_value);
+				map->name, (unsigned long long)sym.st_value);
 			return -LIBBPF_ERRNO__FORMAT;
 		}
 		insn_idx = sym.st_value / BPF_INSN_SZ;