When smc_close_final() returns error, the return code overwrites by
kernel_sock_shutdown() in smc_close_active(). The return code of
smc_close_final() is more important than kernel_sock_shutdown(), and it
will pass to userspace directly.

Fix it by keeping both return codes, if smc_close_final() raises an
error, return it or kernel_sock_shutdown()'s.

Link: https://lore.kernel.org/linux-s390/1f67548e-cbf6-0dce-82b5-10288a4583bd@linux.ibm.com/
Fixes: 606a63c9 ("net/smc: Ensure the active closing peer first closes clcsock")
Suggested-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Acked-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>