wifi: brcmfmac: validate bsscfg indices in IF events

wifi: brcmfmac: validate bsscfg indices in IF events

brcmf_fweh_handle_if_event() validates the firmware-provided interface
index before it touches drvr->iflist[], but it still uses the raw
bsscfgidx field as an array index without a matching range check.

Reject IF events whose bsscfg index does not fit in drvr->iflist[]
before indexing the interface array.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Link: https://patch.msgid.link/20260323074551.93530-1-pengpeng@iscas.ac.cn
[add missing wifi prefix]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>