wifi: iwlwifi: mvm: validate sta_id in BA window status notif

wifi: iwlwifi: mvm: validate sta_id in BA window status notif

BA_WINDOW_STATUS_NOTIFICATION_ID extracts a 5-bit sta_id from the
firmware notification and uses it to index fw_id_to_mac_id[] without
bounds checking. Validate sta_id before array access to prevent
out-of-bounds indexing.

Assisted-by: GitHubCopilot:gpt-5.3-codex
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Link: https://patch.msgid.link/20260714141909.2e97f337f3cb.Ic3f0f404082ccdea13809a3c0b70e0f5417e1037@changeid
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>