cnss2: Assert if MHI resume fails

MHI resume failure is a fatal condition. Assert to debug further.

Change-Id: Ic3b835c8e6d75bb6a31b2561735e7c018168f063
CRs-Fixed: 2741967
Signed-off-by: Mahesh Kumar Kalikot Veetil <mkalikot@codeaurora.org>