opensolaris macros: drop INLINE_FLS checks

[dougm]

Summary

After D40698 is committed, HAS_INLINE_FLS and similar macros will be defined always. This change just removes the tests for these always-true conditions.

[mhorne]

I am not sure where/if this file is used anymore. It originated as part of the Solaris/illumos ZFS implementation, which has been superseded by OpenZFS.

I tried quickly adding an #error directive to the header, but compiling a GENERIC amd64 kernel still succeeded.

In any case, making this change should be fine.