wifi: rsi: bound background scan probe request copy

wifi: rsi: bound background scan probe request copy

rsi_send_bgscan_probe_req() allocates room for struct
rsi_bgscan_probe plus MAX_BGSCAN_PROBE_REQ_LEN bytes, but copies the
entire mac80211-generated probe request skb after the fixed header.
The probe request length depends on scan IEs and is not checked
against the fixed firmware buffer.

Reject generated probe requests that do not fit the firmware command
buffer before copying them into the skb.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Link: https://patch.msgid.link/20260704011231.45593-1-pengpeng@iscas.ac.cn
Signed-off-by: Johannes Berg <johannes.berg@intel.com>