msm: ipa3: Remove ipa_api

ipa_api provided a wrapping layer for various functions in order to
mitigate between different ipa version. This mitigation is no longer
needed, hence ipa_api is obsolete.

Change-Id: I84c3fafef0f578b86080ac8457493ced4ec442e3
Acked-by: Eliad Ben Yishay <ebenyish@qti.qualcomm.com>
Signed-off-by: Amir Levy <alevy@codeaurora.org>