libbpf: Fix spelling mistake "kallasyms" -> "kallsyms"

There is a spelling mistake in a pr_warn message. Fix it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200623084207.149253-1-colin.king@canonical.com

tools/lib/bpf/libbpf.c

@@ -5741,7 +5741,7 @@ static int bpf_object__read_kallsyms_file(struct bpf_object *obj)
 		if (ret == EOF && feof(f))
 			break;
 		if (ret != 3) {
-			pr_warn("failed to read kallasyms entry: %d\n", ret);
+			pr_warn("failed to read kallsyms entry: %d\n", ret);
 			err = -EINVAL;
 			goto out;
 		}