Corrects the Kirkwood dreamplug to use
the right register for power managment. It
was incorrectly using the clock register
which also caused the status to be the
opposite of what it is supposed to be.
1 - its disabled
0 - its enabled

Per kirkwood spec FSS_88F6180_9x_6281_OpenSource.pdf
Clearly split the logic to build ATF and plain tests apart.

This change introduces a new plain.test.mk file that provides the build
infrastructure to build test programs that don't use any framework.
Most of the code previously in bsd.test.mk moves to plain.test.mk and
atf.test.mk is extended with the missing pieces.

In doing so, this change pushes all test program building logic to the
various *.test.mk files instead of trying to reuse some tiny bits.
In fact, this attempt to reuse some definitions makes the code harder
to read and harder to extend.

The clear benefit of this is that the interface of bsd.test.mk is now
clearly delimited.

Submitted by:	Julio Merino jmmv google.com
MFC after:	2 weeks
Add the automatic generation of Atffile files.

These are only used by the deprecated atf-run and atf-report tools.
Generating them is easy and provides a mechanism for people to
experiment with these tools if they wish.

But, because these tools and files are deprecated, doing this only
happens if the user has explicitly set ALLOW_DEPRECATED_ATF_TOOLS
to yes.

Submitted by:	Julio Merino jmmv google.com
MFC after:	2 weeks
Add the automatic generation of Kyuafile files.

These files are generated from bsd.test.mk because kyua is able to run
test programs implemented using different libraries/frameworks.  In
order to make this possible, this change also extends the various
*.test.mk file to explicitly indicate the interface of every test
program.

Submitted by:	Julio Merino jmmv google.com
MFC after:	2 weeks
Plug atf-run into the 'test' target.

If atf-run exists in ATF_PREFIX and if ALLOW_DEPRECATED_ATF_TOOLS has
been set to yes, the test target is automatically defined to use it
for the execution of test programs.

Submitted by:	Julio Merino jmmv google.com
MFC after:	2 weeks
Plug kyua into the 'test' target.

If kyua exists in KYUA_PREFIX, the test target is automatically
defined to use it for the execution of test programs.

Submitted by:	Julio Merino jmmv google.com
MFC after:	2 weeks