msm: ipa: Fix updating the doobell for WDI3

For WDI3, requirement is to ring the event ring DB
with a value outside of the ring. Currently we are taking the
event_ring_size from non SMMU structure which is incorrect.
Make a chane to use the value based on SMMU enablement.
Also make change to ring the DB with the below logic.
Event ring base addr + Event ring size + 1 element size.

Change-Id: Ie9e4cad63070d1488d0a36f9d08279d2d566055a
Signed-off-by: Chaitanya Pratapa <cpratapa@codeaurora.org>