ath10k: Add support for targets without trustzone

Add the support to attach and map iommu
domain for targets which do not have the
support of TrustZone.

Tested HW: WCN3990
Tested FW: WLAN.HL.3.1-01040-QCAHLSWMTPLZ-1

Signed-off-by: Rakesh Pillai <pillair@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1586971906-20985-4-git-send-email-pillair@codeaurora.org