docs: note the removal of gbm_gallium, galahad and identity

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/docs/relnotes/10.6.0.html b/docs/relnotes/10.6.0.html
index a396109..00aaaa5 100644
--- a/docs/relnotes/10.6.0.html
+++ b/docs/relnotes/10.6.0.html
@@ -61,7 +61,10 @@
 <ul>
 <li>Removed classic Windows software rasterizer.</li>
 <li>Removed egl_gallium EGL driver.</li>
+<li>Removed gbm_gallium GBM driver.</li>
 <li>Removed OpenVG support.</li>
+<li>Removed the galahad gallium driver.</li>
+<li>Removed the identity gallium driver.</li>
 </ul>
 
 </div>