qcacld-3.0: Set rx chainmask before start spectral scan

It need rx chainmask to select noise floor when start spectral gen3
scan and rx data by DMA. So set rx chainmask before start spectral
scan.

Change-Id: I63efd8f5384537b5697ba809bb05fdd17e243210
CRs-Fixed: 2519366
4 files changed