meson: move a couple of include installs around

Preparation for a later commit.

Fixes: 93df862b ("meson: re-add incorrect pkg-config files with GLVND for backward compatibility")
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
(cherry picked from commit b9a5fb1f)