cnss2: Add boot support for QCA6290

This is the initial change to support boot for QCA6290 Wi-Fi chipset.
It adds powerup and shutdown hooks for the chipset.

Change-Id: I0182f8ae60dcaf95db1759bcc4cc5f670a7e9138
Signed-off-by: Yue Ma <yuem@codeaurora.org>