msm: ipa: Fix to initialize IPA_CLIENT_Q6_WAN_PROD

IPA_CLIENT_Q6_WAN_PROD pipe is used starting from 3.0. Update ep_mapping
table for lesser HW versions with -1 so that stale value is not used.

Change-Id: Ifdcde9f517555cd869ae1882ea0c53f5b760098a
Acked-by: Chaitanya Pratapa <cpratapa@qti.qualcomm.com>
Signed-off-by: Ravinder Konka <rkonka@codeaurora.org>