mhi: core: process incoming data based on event ring type

mhi clients can manage both hardware and software event rings.
Process incoming data based on event ring type instead of
channel type.

CRs-Fixed: 2018326
Change-Id: Ifa2de76034224c19a846f7be153400888f8c66de
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>