RDMA/cxgb4: Remove unused declarations

Since commit be4c9bad ("MAINTAINERS: Add cxgb4 and iw_cxgb4 entries")
c4iw_post_terminate() declaration is not used anymore.

And other declarations were never implemented since introduction in
commit cfdda9d7 ("RDMA/cxgb4: Add driver for Chelsio T4 RNIC").

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://patch.msgid.link/20240824091629.3659565-1-yuehaibing@huawei.com


Signed-off-by: Leon Romanovsky <leon@kernel.org>