cnss2: remove deprecated IOMMU APIs

IOMMU mapping APIs have been deprecated in favor of device
tree entries. Update CNSS functions as required. Keep the
old API and structure for backward compatibility. They will
be removed once WLAN driver switch to the new APIs.

CRs-Fixed: 2409946
Change-Id: I8b50fefd0acd9e48670e350d20da7b0633e336b3
Signed-off-by: Yuanyuan Liu <yuanliu@codeaurora.org>