softpll and userspace: massive changes

[this commit message by Alessandro]

This is a set of changes that bring upstream the internal status of
Tom's machine.  Splitting them up would be a massive work to little
benefit, since this is obviously right.

The broken symlink in the original commit in "tom-rt-fixes" branch is
fixed in this rebased commit.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>