i915: Actually enable __DRI2rendererQueryExtensionRec

More rebase fail.  This code was written long before i915 and i965 were
split, so most of the code in i9[16]5/intel_screen.c only needed to
exist in one place.  It looks like I fixed n-1 of those places after
rebasing on the split.

I only found this from the defined-but-not-used warning for
intelRendererQueryExtension.  I noticed this while fixing the other,
related warnings.

(Note: During review, we decided to *not* pick this back to 10.0.)

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Paul Berry <stereotype441@gmail.com>

src/mesa/drivers/dri/i915/intel_screen.c

@@ -790,6 +790,7 @@ static const __DRIextension *intelScreenExtensions[] = {
     &intelTexBufferExtension.base,
     &intelFlushExtension.base,
     &intelImageExtension.base,
+    &intelRendererQueryExtension.base,
     &dri2ConfigQueryExtension.base,
     NULL
 };