libxfs: print the device name if flush-on-close fails

libxfs: print the device name if flush-on-close fails

Print the name of the device if persisting the write cache fails.
Printing a pointer does not help the user at all, and this causes the
32-bit build to complain:

init.c: In function ‘libxfs_device_close’:
init.c:178:35: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  178 |                         progname, (long long)dev, ret);
      |                                   ^
cc1: all warnings being treated as errors

Fixes: fc83c7574b1f ("libxfs: split out a libxfs_dev structure from struct libxfs_init")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>