msm: ipa: handle IPA RM timer destruction correctly

Previously, the operation did not account for the fact
that the timer could be active i.e. on one of the timer
lists pending expiry. Later when timer expired, the timer
context was invalid leading to a crash.

Change-Id: Ic39abcabc3d34f96156e2dea36c3b0a77b4846dd
Signed-off-by: Ravi Gummadidala <rgummadi@codeaurora.org>