`end` parameter is no needed since it's pointless for !backmost, we can
handle it with backmost internally. And we only expand the trailing
edge, so the newstart can be replaced with ->headoffset.
Also, remove linux/prefetch.h inclusion since that is not used anymore
after commit 386292919c ("erofs: introduce readmore decompression
strategy").
Signed-off-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230525072605.17857-1-zbestahu@gmail.com
[ Gao Xiang: update commit description. ]
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
796e9149a2