RDMA/hns: Solve the overflow of the calc_pg_sz()

calc_pg_sz() may gets a data calculation overflow if the PAGE_SIZE is 64 KB
and hop_num is 2. It is because that all variables involved in calculation
are defined in type of int. So change the type of bt_chunk_size,
buf_chunk_size and obj_per_chunk_default to u64.

Fixes: ba6bb7e9 ("RDMA/hns: Add interfaces to get pf capabilities from firmware")
Link: https://lore.kernel.org/r/1600509802-44382-6-git-send-email-liweihang@huawei.comSigned-off-by: Jiaran Zhang <zhangjiaran@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

@@ -1800,9 +1800,9 @@ static void calc_pg_sz(int obj_num, int obj_size, int hop_num, int ctx_bt_num,
 		       int *buf_page_size, int *bt_page_size, u32 hem_type)
 {
 	u64 obj_per_chunk;
-	int bt_chunk_size = 1 << PAGE_SHIFT;
-	int buf_chunk_size = 1 << PAGE_SHIFT;
-	int obj_per_chunk_default = buf_chunk_size / obj_size;
+	u64 bt_chunk_size = PAGE_SIZE;
+	u64 buf_chunk_size = PAGE_SIZE;
+	u64 obj_per_chunk_default = buf_chunk_size / obj_size;
 
 	*buf_page_size = 0;
 	*bt_page_size = 0;