msm: ipa: add support to modify filter rules

This enables existing filter rules to be modified in
place. The filter rule index remains unchanged. This
change is needed to simplify client logic.

Change-Id: I97f5247288d3ca69209ee4f141fd324b8b2665e8
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>