nvmet-fc: fix endianess annoations for nvmet_fc_format_rsp_hdr

The passed in desc_len is a big endian value, so mark it as such.

Found by sparse.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

drivers/nvme/target/fc.c

@@ -1058,7 +1058,7 @@ EXPORT_SYMBOL_GPL(nvmet_fc_unregister_targetport);
 
 
 static void
-nvmet_fc_format_rsp_hdr(void *buf, u8 ls_cmd, u32 desc_len, u8 rqst_ls_cmd)
+nvmet_fc_format_rsp_hdr(void *buf, u8 ls_cmd, __be32 desc_len, u8 rqst_ls_cmd)
 {
 	struct fcnvme_ls_acc_hdr *acc = buf;