Converting the Makefile to use the new tools buildsystem.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
[fixes builds with O=...]
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200819071733.60028-1-heikki.krogerus@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>