net: cnss2: Add snapshot of CNSS2 driver

This is a snapshot of the CNSS2 driver and associated files as of
msm-4.14 commit b836faab20de
(cnss2: Do not suspend MHI if PCIe is not going to be suspended).

Checkpatch issues are also fixed on top of this commit.

CRs-Fixed: 2375545
Change-Id: Ia6d6624a17b92c6d3c64cf1a9dd4df489389fb45
Signed-off-by: Yuanyuan Liu <yuanliu@codeaurora.org>