slim_msm: Remove active channels of a satellite when it restarts

When a subsystem hosting satellite restarts, it may not have cleaned
up its active channels. Remove all active channels when this is
detected. Other satellites, and channels already removed (if cleanup
was executed on the subsystem hosting satellite) are not affected.

Change-Id: I50ac40e450335a4fa5be957bacf997311410bee1
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>