libbpf: Remove several dead assignments

Clang Static Analyzer (scan-build) reports several dead assignments in
libbpf where the assigned value is unconditionally overridden by another
value before it is read. Remove these assignments.

Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/5503d18966583e55158471ebbb2f67374b11bf5e.1677658777.git.vmalik@redhat.com

tools/lib/bpf/btf.c

@@ -1000,8 +1000,6 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
 		}
 	}
 
-	err = 0;
-
 	if (!btf_data) {
 		pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path);
 		err = -ENODATA;

tools/lib/bpf/libbpf.c

@@ -798,7 +798,6 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
 	progs = obj->programs;
 	nr_progs = obj->nr_programs;
 	nr_syms = symbols->d_size / sizeof(Elf64_Sym);
-	sec_off = 0;
 
 	for (i = 0; i < nr_syms; i++) {
 		sym = elf_sym_by_idx(obj, i);

tools/lib/bpf/relo_core.c

@@ -1551,9 +1551,6 @@ int __bpf_core_types_match(const struct btf *local_btf, __u32 local_id, const st
 	if (level <= 0)
 		return -EINVAL;
 
-	local_t = btf_type_by_id(local_btf, local_id);
-	targ_t = btf_type_by_id(targ_btf, targ_id);
-
 recur:
 	depth--;
 	if (depth < 0)