RDMA/rxe: Fix __bth_set_resv6a

__bth_set_resv6a is used to clear BIT [24, 29] of rxe_bth::qpn, the
wrong expression leads other BITs into 1.

Link: https://patch.msgid.link/r/20240822065223.1117056-4-pizhenwei@bytedance.comSigned-off-by: zhenwei pi <pizhenwei@bytedance.com>
Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_hdr.h

@@ -234,7 +234,7 @@ static inline void __bth_set_resv6a(void *arg)
 {
 	struct rxe_bth *bth = arg;
 
-	bth->qpn = cpu_to_be32(~BTH_RESV6A_MASK);
+	bth->qpn &= cpu_to_be32(~BTH_RESV6A_MASK);
 }
 
 static inline int __bth_ack(void *arg)