octeontx2-pf: Skip dma map and unmap when IOMMU is bypassed

commit 4715f5a153e830a84ffb5a2049449c1912dd7eac from
git@git.assembla.com:cavium/WindRiver.linux.git

HW takes care of data coherency at LLC level, to save some
CPU cycles skip calling dma_map and dma_unmap apis when
IOMMU is bypassed. This improves IP forwarding performance
by ~5%. These changes are not for upstream.

Change-Id: Ie1be6982d62ffe4bbb4434092c0c5ce3575d9339
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/19664


Tested-by: sa_ip-sw-jenkins <sa_ip-sw-jenkins@marvell.com>
Reviewed-by: Sunil Kovvuri Goutham <Sunil.Goutham@cavium.com>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>