cnic: Refactor code in cnic_cm_process_kcqe().

Move chip-specific code to the respective chip's ->close_conn() functions
for better code organization.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Eddie Wai <waie@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>