net/smc: introduce sub-functions for smc_clc_send_confirm_accept()

[ Upstream commit 5205ac44 ]

There is a large if-else block in smc_clc_send_confirm_accept() and it
is better to split it into two sub-functions.

Suggested-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 0541db8e ("net/smc: initialize close_work early to avoid warning")
Signed-off-by: Sasha Levin <sashal@kernel.org>