mhi: netdev: Avoid free of netdev client,ipc handles

Change involves to avoid free of mhi netdev client, ipc handles
as part of mhi_dev_net_state_cb(). These are not re-allocated in
mhi_dev_net_interface_init() as mhi_net_ctxt.client_handle is
already valid which is called during device reset scenario.

Change-Id: I6f660c8dccd47a93c115c39d2898f450c5d61635
Signed-off-by: Subramanian Ananthanarayanan <skananth@codeaurora.org>