cnss2: Assert if MHI is in bad states for debug purpose

Currently even if MHI states are out of order, driver can still
handle but may casue other issues later and logs getting flooded.
In order to expose the real issue, assert if MHI is in bad states
in debug build only.

Change-Id: Icb57ea8100cb11fccc54978fbcc62167bdba2818
Signed-off-by: Yue Ma <yuem@codeaurora.org>