msm: mhi_dev: Avoiding freeing of ereq memory in reset

With the commit <1528bbe6> ("msm: mhi_dev: Keeping event req
memory without clearing in close channel"), we are avoiding freeing
of ereq memory in close channel API. New memory is not created again
as part of start/open channel since it is not released while closing
the channel. Idea is to hold the allocated memory and avoid
reallocating every time.

But during the reset command we are freeing some of the ereqs which we
need to hold without releasing.

This change avoids freeing of ereq memory as part of reset channel
command and adds the ereqs to the event_req_buffers list. This ensures
that the lists, event_req_buffers and flush_event_req_buffers are
updated with valid ereqs.

Change-Id: Ie29962f2bc8ef5a0c193d13a13118ae9b6044c0b
Signed-off-by: Sai Chaitanya Kaveti <quic_skaveti@quicinc.com>