wifi: cfg80211: fix out-of-bounds access during multi-link element defragmentation

Currently during the multi-link element defragmentation process, the
multi-link element length added to the total IEs length when calculating
the length of remaining IEs after the multi-link element in
cfg80211_defrag_mle(). This could lead to out-of-bounds access if the
multi-link element or its corresponding fragment elements are the last
elements in the IEs buffer.

To address this issue, correctly calculate the remaining IEs length by
deducting the multi-link element end offset from total IEs end offset.

Cc: stable@vger.kernel.org
Fixes: 2481b5da ("wifi: cfg80211: handle BSS data contained in ML probe responses")
Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>
Link: https://patch.msgid.link/20250424-fix_mle_defragmentation_oob_access-v1-1-84412a1743fa@quicinc.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>