msm: ipa: merge ipa_gsi_ep_info into ipa3_ep_mapping

On msmskunk, an IPA endpoint can be used for more then one configuration,
where each configuration has its own set of parameters. Therefore, the
endpoint configuration cannot be saved as an array according to endpoint
index.

CRs-Fixed: 1097871
Change-Id: I74e1a61e5785a0a80c5e164dd4cf8e98e385cb17
Signed-off-by: Gidon Studinski <gidons@codeaurora.org>
Signed-off-by: Amir Levy <alevy@codeaurora.org>