randr: call RRProviderInit in the proper place.

No idea where this got lost across development cycles, but its
definitely missing.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=57448

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

randr/randr.c

@@ -264,6 +264,8 @@ RRInit(void)
             return FALSE;
         if (!RROutputInit())
             return FALSE;
+        if (!RRProviderInit())
+            return FALSE;
         RRGeneration = serverGeneration;
     }
     if (!dixRegisterPrivateKey(&rrPrivKeyRec, PRIVATE_SCREEN, 0))