msm: mhi_dev: Support device reset

When host issues a MHI (modem host interface) device
reset the existing cache context for channel, events
and command needs to be invalidated. IPA needs to be
released including rest of hardware channels and device
needs to prepare to perform a fresh start. Abort all
pending software data transfers, reset the MHI state
and channels, reset MMIO. Once host detects complete
device reset it re-initializes MHI MMIO and device
needs to cache the new context and prepare for data
transfers.

Change-Id: I20c4feb03cbcc56da070848e92294c70c31e0575
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>