LoongArch: BPF: Rename and refactor validate_code()

1. Rename the existing validate_code() to validate_ctx()
2. Factor out the code validation handling into a new helper
   validate_code()

Then:

* validate_code() is used to check the validity of code.
* validate_ctx() is used to check both code validity and table entry
  correctness.

The new validate_code() will be used in subsequent changes.

Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com>
Co-developed-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: George Guo <guodongtai@kylinos.cn>
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: Chenghao Duan

arch/loongarch/net/bpf_jit.c

@@ -1180,6 +1180,14 @@ static int validate_code(struct jit_ctx *ctx)
 			return -1;
 	}
 
+	return 0;
+}
+
+static int validate_ctx(struct jit_ctx *ctx)
+{
+	if (validate_code(ctx))
+		return -1;
+
 	if (WARN_ON_ONCE(ctx->num_exentries != ctx->prog->aux->num_exentries))
 		return -1;
 
@@ -1288,7 +1296,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	build_epilogue(&ctx);
 
 	/* 3. Extra pass to validate JITed code */
-	if (validate_code(&ctx)) {
+	if (validate_ctx(&ctx)) {
 		bpf_jit_binary_free(header);
 		prog = orig_prog;
 		goto out_offset;