This also removes PKG_BUILD_PARALLEL:=0 that was added for packages that
use HOST_PYTHON3_PACKAGE_BUILD_DEPENDS.
Signed-off-by: Jeffery To <jeffery.to@gmail.com>
The Python package will be installed in `$(STAGING_DIR_HOSTPKG)/lib/pythonX.Y/site-packages`.
The Python package will be installed in `$(STAGING_DIR_HOSTPKG)/lib/pythonX.Y/site-packages`.
Parallel builds need to be disabled because installing packages with multiple concurrent pip processes can lead to [errors or unexpected results](https://github.com/pypa/pip/issues/2361).