cnss2: Do not deinit MHI right after powerup failure

Immediately deinit MHI after powerup failure will clear all the
MHI context so it won't be able to enter RDDM state to collect
firmware RAM dump. Leave the cleanup to SSR shutdown routine.

Change-Id: Ibbbe3ffe3c471f69dd4fc89d7cfaf57f1f899a92
CRs-fixed: 2059087
Signed-off-by: Yue Ma <yuem@codeaurora.org>