msm: ipa3: fix event ring allocation for PROD

Do not allocate event ring for non interrupts pipes.
These pipes receive completion from their
status notification pipe.

Change-Id: I9ae96440ed479888e2f974f2143ddd275f8afbb2
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>