slim_ngd: Return success for resource removal requests if HW restarts

Channel and ports are removed when HW restarts. Return success to
client channel removal, port disconnection requests when slimbus HW
is restarting.

Change-Id: Ifc9a3bb80023c823a7776a16fe32e5b59b181350
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>