acpi(4): Always compile the files dealing with ACPI_DEBUG into the module.

acpi(4): Always compile the files dealing with ACPI_DEBUG into the module.

Before this commit, one had to define ACPI_DEBUG as a make variable to
enable debugging support in the module, such as in:

$ make -DACPI_DEBUG buildkernel

Specifying ACPI_DEBUG in the kernel config alone did not enable it, but
our modules are supposed to honor kernel options. Also this was contrary
to what the manual page says.

So to make this work for ACPI_DEBUG too, we just put all the affected
source files into SRCS and always compile them. #ifdef's in these
source files will take care of enabling/disabling debugging support
so a module compiled without ACPI_DEBUG defined in the kernel or on the
command line will still not have support after this commit (I've checked
with nm(1)).

The only change for someone not using ACPI_DEBUG is a little bit of
additional buildkernel time.

FWIW, it is the same way in FreeBSD, too.

Reported-by: Andrea Magliano <masterblaster@tiscali.it>