mesa-demos: Build with system data files

mesa-demos: Build with system data files

Use the "--with-system-data-files" when configuring mesa-demos
so that the data files in /usr/share/mesa-demos/ will be properly
located at run time.

Copy some additional data files into the target filesystem.

Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>