wifi: ath12k: bring DFS support back for WCN7850

Due to the restrict in MAC80211 that DFS (Dynamic Frequency Selection)
can't be enabled on multiple channels, commit 176f3009 ("wifi: ath12k:
support 2 channels for single pdev device") removes DFS support in order
to support 2 channels concurrently, making AP mode not working on DFS
channels [1].

Revert portions of that commit to bring DFS back, and add a new
combination to support 2-channels concurrency. This is valid because the
MAC80211 restrict works on each individual combination, but does not care
about them as a whole, as far as DFS is concerned.

This change applies to WCN7850 only, other chips are not affected.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00284.1-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: 176f3009 ("wifi: ath12k: support 2 channels for single pdev device")
Reported-by: Mihai Moldovan <ionic@ionic.de>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220346

 # 1
Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Link: https://patch.msgid.link/20250721-ath12k-dfs-v1-1-065c31454f91@oss.qualcomm.com


Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>