net/smc: Fix smc_link->llc_testlink_time overflow

The value of llc_testlink_time is set to the value stored in
net->ipv4.sysctl_tcp_keepalive_time when linkgroup init. The value of
sysctl_tcp_keepalive_time is already jiffies, so we don't need to
multiply by HZ, which would cause smc_link->llc_testlink_time overflow,
and test_link send flood.

Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>