meson: strip rpath from megadrivers

More specifically, use the library file that has been post-processed by Meson
when creating the hardlinks.

Bugs: https://bugs.freedesktop.org/show_bug.cgi?id=108766
Fixes: 3218056e0e "meson: Build i965 and dri stack"
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>

bin/install_megadrivers.py

@@ -49,7 +49,6 @@ def main():
         if os.path.lexists(to):
             os.unlink(to)
         os.makedirs(to)
-    shutil.copy(args.megadriver, master)
 
     for driver in args.drivers:
         abs_driver = os.path.join(to, driver)