wifi: cfg80211: Set correct chandef when starting CAC

In the Linux kernel, the following vulnerability has been resolved:

wifi: cfg80211: Set correct chandef when starting CAC

When starting CAC in a mode other than AP mode, it return a

"WARNING: CPU: 0 PID: 63 at cfg80211_chandef_dfs_usable+0x20/0xaf [cfg80211]"

caused by the chandef.chan being null at the end of CAC.

Solution: Ensure the channel definition is set for the different modes

when starting CAC to avoid getting a NULL 'chan' at the end of CAC.

Call Trace:

? show_regs.part.0+0x14/0x16

? __warn+0x67/0xc0

? cfg80211_chandef_dfs_usable+0x20/0xaf [cfg80211]

? report_bug+0xa7/0x130

? exc_overflow+0x30/0x30

? handle_bug+0x27/0x50

? exc_invalid_op+0x18/0x60

? handle_exception+0xf6/0xf6

? exc_overflow+0x30/0x30

? cfg80211_chandef_dfs_usable+0x20/0xaf [cfg80211]

? exc_overflow+0x30/0x30

? cfg80211_chandef_dfs_usable+0x20/0xaf [cfg80211]

? regulatory_propagate_dfs_state.cold+0x1b/0x4c [cfg80211]

? cfg80211_propagate_cac_done_wk+0x1a/0x30 [cfg80211]

? process_one_work+0x165/0x280

? worker_thread+0x120/0x3f0

? kthread+0xc2/0xf0

? process_one_work+0x280/0x280

? kthread_complete_and_exit+0x20/0x20

? ret_from_fork+0x19/0x24

[shorten subject, remove OCB, reorder cases to match previous list]