mhi: core: Do not reset doorbell mode during MHI_M3 abort

In order to avoid being out of sync between MHI client
and MHI host, host shall not reset the doorbell modes for
hardware channels during MHI_M3 state transition abort.

CRs-Fixed: 1023725
Change-Id: I6c742fc968fd57d71a86039bf1f3f65b1362bc90
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>