cnss2: Move power on and bus init to the end of platform probe call

Device power on and bus init should happen when all platform related
init are done since it means all platform configs are ready and it is
good to bring up device. Hence move them to the end of platform probe
call.

Change-Id: I22a69be4a25de6f8c45994dca23f6f631fd1474f
Signed-off-by: Yue Ma <yuem@codeaurora.org>