net/smc: remove unused function smc_lo_supports_v2

The smcd_ops->supports_v2 is only called in smcd_register_dev(), which
calls function smcd_supports_v2 for ism. For loopback-ism, function
smc_lo_supports_v2 is unused, remove it.

Signed-off-by: Wang Liang <wangliang74@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250619030854.1536676-1-wangliang74@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>