ctcm: fix minor findings from code analysis tool

From: Ursula Braun <ursula.braun@de.ibm.com>

This patch fixes problems in the ctcm driver identified by
static code analysis:
o remove an unnecessary always true condition in ctcm_unpack_skb
o remove duplicate assignment in ctc_mpc_alloc_channel
o remove an unnecessary always true condition in ctcmpc_send_sweep_resp
o remove duplicate initialization in ctcmpc_unpack_skb
o shorten if condition in mpc_action_go_inop
o remove INOP event if mpc group is undefined in mpc_action_doxid7

Signed-off-by: Joel A. Fowler <fowlerja@us.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>