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: 3218056e "meson: Build i965 and dri stack"
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
(cherry picked from commit aa7afe32)