svn commit: r339618 - head/sys/compat/linuxkpi/common/include/linux

[Matthew Macy]

> Note that these functions are normally used on uncacheable memory which
> is strongly ordered on x86.  There should be no reordering at all.  On
> PowerPC barrier instructions are needed to prevent reordering.

Correct. The current lkpi implementation also assumes that device
endian == host endian. The Linux generic accessors will do use endian
macros to byte swap where necessary.

The following change fixes radeon attach issues:
https://github.com/POWER9BSD/freebsd/commit/be6c98f5c2e2ed9a4935ac5b67c468b75f3b4457