net/smc: extend smc_llc_send_add_link() and smc_llc_send_delete_link()

net/smc: extend smc_llc_send_add_link() and smc_llc_send_delete_link()

All LLC sends are done from worker context only, so remove the prep
functions which were used to build the message before it was sent, and
add the function content into the respective send function
smc_llc_send_add_link() and smc_llc_send_delete_link().
Extend smc_llc_send_add_link() to include the qp_mtu value in the LLC
message, which is needed to establish a link after the initial link was
created. Extend smc_llc_send_delete_link() to contain a link_id and a
reason code for the link deletion in the LLC message, which is needed
when a specific link should be deleted.
And add the list of existing DELETE_LINK reason codes.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>