msm: ipa: add support to specify exception EP for given interface

This information is needed to install routing rules for SW processing
of packets belonging to this interface

Change-Id: Ic0f34e5e7a3e8eb1808a3214e63bc71d1f6d4ede
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>