msm: ipa: add support for packet length update

Add support for IPA uC to update packet length field
in client header.

Change-Id: I11021aa3e81bd75acd71797de53d57262de0c3ea
Acked-by: Shihuan Liu <shihuanl@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>