ps3vram: remove bio splitting

ps3vram iterates over the bio one segment, that is page aligned and max
page sized chunk, a time.  Because of that there is no point in
calling bio_split_to_limits, or explicitly setting the default limits
that are only used by bio_split_to_limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Geoff Levand <geoff@infradead.org>
Link: https://lore.kernel.org/r/20230123074718.57951-1-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>