CVE-2026-68197 wifi: mwifiex: fix NULL dereference when the AP has HT-cap but no HT-oper

In the Linux kernel, the following vulnerability has been resolved: wifi: mwifiex: fix NULL dereference when the AP has HT-cap but no HT-oper mwifiextdlsaddhtoper gates its follow-the-AP-bandwidth path on bssdesc-bcnhtcap being present, but then dereferences a different pointer, bssdesc-bcnhtoper...