CVE-2023-52827

In the Linux kernel, the following vulnerability has been resolved:

wifi: ath12k: fix possible out-of-bound read in ath12k_htt_pull_ppdu_stats()

len is extracted from HTT message and could be an unexpected value in
case errors happen, so add validation before using to avoid possible
out-of-bound read in the following message iteration and parsing.

The same issue also applies to ppdu_info->ppdu_stats.common.num_users,
so validate it before using too.

These are found during code review.

Compile test only.