IB/qib: Remove unused declarations in header file

The definition of qib_rc_rnr_retry() has been removed since
commit b4238e70 ("IB/qib: Use new rdmavt timers"). Also, the definition
of mr_rcu_callback() has been remove since commit 7c2e11fe ("IB/qib:
Remove qp and mr functionality from qib"). So, let's remove the unused
declartions.
Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Link: https://patch.msgid.link/20240909121408.80079-3-zhangzekun11@huawei.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/qib/qib_verbs.h

@@ -303,8 +303,6 @@ int qib_check_send_wqe(struct rvt_qp *qp, struct rvt_swqe *wqe,
 
 struct ib_ah *qib_create_qp0_ah(struct qib_ibport *ibp, u16 dlid);
 
-void qib_rc_rnr_retry(unsigned long arg);
-
 void qib_rc_send_complete(struct rvt_qp *qp, struct ib_header *hdr);
 
 int qib_post_ud_send(struct rvt_qp *qp, const struct ib_send_wr *wr);
@@ -312,8 +310,6 @@ int qib_post_ud_send(struct rvt_qp *qp, const struct ib_send_wr *wr);
 void qib_ud_rcv(struct qib_ibport *ibp, struct ib_header *hdr,
 		int has_grh, void *data, u32 tlen, struct rvt_qp *qp);
 
-void mr_rcu_callback(struct rcu_head *list);
-
 void qib_migrate_qp(struct rvt_qp *qp);
 
 int qib_ruc_check_hdr(struct qib_ibport *ibp, struct ib_header *hdr,