MHI PM state for suspended states needs to be checked under pm_lock,
otherwise MHI host could miss transition state and result in a
data stall.
CRs-Fixed: 2279502
Change-Id: I55cdfb1d5ab5fc745a0e06977c89a18e412c6129
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>