cifs: convert to use be32_add_cpu()

Convert cpu_to_be32(be32_to_cpu(E1) + E2) to use be32_add_cpu().

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a61abde..fe4b559 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -5114,8 +5114,7 @@ CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
 	bcc_ptr += strlen("?????");
 	bcc_ptr += 1;
 	count = bcc_ptr - &pSMB->Password[0];
-	pSMB->hdr.smb_buf_length = cpu_to_be32(be32_to_cpu(
-					pSMB->hdr.smb_buf_length) + count);
+	be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
 	pSMB->ByteCount = cpu_to_le16(count);
 
 	rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,