qcacld-3.0: Downgrade channel bandwidth for DBS2

In DBS mode 2x2 VHT40 2G and 1x1 VHT 40 5G, the MAC 1 (5G)
doesn't support VHT80. Update the ch_width to max of 40Mhz
in beacon OMN ie when switch to DBS2.

Change-Id: If5cf65bca815d1e8df67a1515b2fb3edcba52a8e
CRs-Fixed: 2520719
8 files changed