WCN3990 is integrated 802.11ac chipset with SNOC
bus interface. Add snoc layer driver registration
and associated ops.

WCN3990 support is not yet complete as cold-boot
handshake is done using qmi(Qualcomm-MSM-Interface)
and qmi client support will be added once qmi framework
is available.
Signed-off-by: Govind Singh <govinds@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>