PATCH reiser4 support for Linux 5.8.10

[David Niklas]

I'm a kernel dev newbie. Please double check my work if in doubt.

The patch for reiser4 support for Linux 5.8.1 didn't apply to 5.8.10. It
needed only a one line change, but because of all the fuzzy matching and
offset matching I thought I'd make a new one.
The file that failed to patch is fs/fs-writeback.c. A struct got one of
it's members removed. As the entire struct was removed by the patch I
thought it good to ignore the missing member instead of trying to dig up
what it was used for and why it was removed.

Thanks,
David