In nvme_tcp_ddgst_update(), sg_init_marker() is called with an
uninitialized scatterlist. This is probably fine, but gcc complains:

  CC [M]  drivers/nvme/host/tcp.o
In file included from ./include/linux/dma-mapping.h:10,
                 from ./include/linux/skbuff.h:31,
                 from ./include/net/net_namespace.h:43,
                 from ./include/linux/netdevice.h:38,
                 from ./include/net/sock.h:46,
                 from drivers/nvme/host/tcp.c:12:
In function ‘sg_mark_end’,
    inlined from ‘sg_init_marker’ at ./include/linux/scatterlist.h:356:2,
    inlined from ‘nvme_tcp_ddgst_update’ at drivers/nvme/host/tcp.c:390:2:
./include/linux/scatterlist.h:234:11: error: ‘sg.page_link’ is used uninitialized [-Werror=uninitialized]
  234 |         sg->page_link |= SG_END;
      |         ~~^~~~~~~~~~~
drivers/nvme/host/tcp.c: In function ‘nvme_tcp_ddgst_update’:
drivers/nvme/host/tcp.c:388:28: note: ‘sg’ declared here
  388 |         struct scatterlist sg;
      |                            ^~
cc1: all warnings being treated as errors

Use sg_init_table() instead, which basically memset the scatterlist to
zero first before calling sg_init_marker().
Signed-off-by: Nam Cao <namcaov@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>