wifi: nl80211: Avoid address calculations via out of bounds array indexing

In the Linux kernel, the following vulnerability has been resolved: wifi: nl80211: Avoid address calculations via out of bounds array indexing Before request->channels[] can be used, request->n_channels must be set. Additionally, address calculations for memory after the "channels" array need to be calculated from the allocation base ("request") rather than via the first "out of bounds" index of "channels", otherwise run-time bounds checking will throw a warning.