UPSTREAM: ath10k: add hif tx methods for wcn3990

Add hif tx/tx-complete methods for wcn3990
target.

Signed-off-by: Govind Singh <govinds@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Git-commit: d390509bdf501c9c8c6e61248e4bc9314c86d854
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


Change-Id: I2730d8e4df80181356820d053d314c1a664fb9e5
Signed-off-by: Dundi Raviteja <dundi@codeaurora.org>