RDMA/cxgb3: Delete and properly mark unimplemented resize CQ function

Resize CQ implementation was guarded by undeclared "notyet" define while
cxgb3 was added to the kernel. Twelve years later, this call is still
unimplemented, so safely delete it and fix improper return error code when
.resize_cq() is not implemented.

Fixes: b038ced7 ("RDMA/cxgb3: Add driver for Chelsio T3 RNIC")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>