tests: generate dtbs in Meson build directory

[blmaier]

When running under Meson, check_tests() is generating dtb build files in the source directory. This is because dtb is named by appending ".test.dtb" to the full source file name.

Use basename to extract just the source filename and write it to the working directory which is the build directory.

[dgibson]

There are also some files created incorrectly under pylibfdt/ with a meson build, but that can certainly be fixed as a separate patch.

[blmaier]

There are also some files created incorrectly under pylibfdt/ with a meson build, but that can certainly be fixed as a separate patch.

I was looking at those, they are significantly more complicated to fix as they are generated in the backend of distutils and swig.

[dgibson]

There are also some files created incorrectly under pylibfdt/ with a meson build, but that can certainly be fixed as a separate patch.

I was looking at those, they are significantly more complicated to fix as they are generated in the backend of distutils and swig.

That doesn't surprise me. Oh well, maybe one day.

[dgibson]

Merged, thanks!