va: drop no longer applicable vaGetDriverNames check

All the backends implement the callback. So this temporary check can go
now.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/va/va.c b/va/va.c
index 4e6a4a9..920b76c 100644
--- a/va/va.c
+++ b/va/va.c
@@ -674,10 +674,6 @@
     const char *driver_name_env;
     VADriverContextP ctx;
 
-    /* XXX: Temporary dummy return, until all platforms are converted */
-    if (!pDisplayContext->vaGetDriverNames)
-        return VA_STATUS_ERROR_INVALID_PARAMETER;
-
     /* XXX: The order is bonkers - env var should take highest priority, then
      * override (which ought to be nuked) than native. It's not possible atm,
      * since the DPY connect/init happens during the GetDriverNames.