qcacmn: dfs memory leak fixed
dfs_detach function was called from ol/lmac layer during ath_detach.
To fix the memory leak dfs_detach function called from dfs pdev
destroy function.
Change-Id: I41602c17ac9ab0b6eb1e9fbe9abe764d00ed0e93
CRs-Fixed: 2001106