libbpf: Remove unneeded check for flags during tc detach

Coverity complained about this being unreachable code. It is right
because we already enforce flags to be unset, so a check validating
the flag value is redundant.

Fixes: 715c5ce4 ("libbpf: Add low level TC-BPF management API")
Signed-off-by: NKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210612023502.1283837-2-memxor@gmail.com

tools/lib/bpf/netlink.c

@@ -675,8 +675,6 @@ static int __bpf_tc_detach(const struct bpf_tc_hook *hook,
 		return -EINVAL;
 	if (priority > UINT16_MAX)
 		return -EINVAL;
-	if (flags & ~BPF_TC_F_REPLACE)
-		return -EINVAL;
 	if (!flush) {
 		if (!handle || !priority)
 			return -EINVAL;