msm: ipa: fix memory leak on QMI

Fix a memory leak in case tethering stats
QMI message failed.

Change-Id: I90457b5dec2e8f2105f37978de57954cdaf9aa08
CRs-Fixed: 1055880
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>