msm: ipa: bug fix for driver handling of dropped packets

This change fixes the IPA driver handling of
packets being dropped by IPA core.
Without this change, IPA driver ignores the IPA core
notification for dropped packets, ignoring IPA core
notification causes IPA driver state be incorrect due
to the fact that IPA driver holds a list of outstanding
transmitted packets. so in case of ignoring dropped
packet IPA driver will keep a wrong outstanding list.
This change add support for dropped packets in IPA driver.

Change-Id: I2a447336de2055c24e4a3fad213469c8eacc4884
Signed-off-by: Talel Shenhar <tatias@codeaurora.org>