smc: Remove unused function.

net/smc/smc_llc.c:544:12: warning: ‘smc_llc_alloc_alt_link’ defined but not used [-Wunused-function]
 static int smc_llc_alloc_alt_link(struct smc_link_group *lgr,
            ^~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: David S. Miller <davem@davemloft.net>