cnss2: Sync code from kernel 4.14

Sync cnss2 codes to kernel 4.9 from kernel 4.14 for
qca6595 and qca6696. The code from 4.14 is based on
the commit:a9567eae9d979dcf83e73ef4e31d4ecbdb553e70 in
msm-4.14. Because the APIs of qmi are not updated with
4.14, so keep these qmi interfaces.

Add the description of cnss-qca-converged in cnss-wlan.txt.

CRs-Fixed: 2685017
Change-Id: I88a6d3a7dd4bd8209cd7aa83336b48fc1f0371e0
Signed-off-by: Kuichu Ni <kuichun@codeaurora.org>