fully convert f2fs to the new bio allocation interface

[Christoph Hellwig]

Hi Jaegeuk and Chao,

as of the for-5.18/block tree, the bio allocation interfaces expect the
block_device and operation passed.  This fixes f2fs up to match that
scheme.

It could go into Jens' alloc-cleanups branch if there are no conflicts
in the f2fs tree.