drm/i915: Use chipset-specific irq installers

Konstantin Belousov pointed out that 4697995b replaced the generic
i915_driver_irq_*install() functions with chipset specific routines
accessible only through driver->irq_*install(). So update the sanity
check in i915_request_wait() to match.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NKeith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -2080,8 +2080,8 @@ i915_wait_request(struct intel_ring_buffer *ring,
 		if (!ier) {
 			DRM_ERROR("something (likely vbetool) disabled "
 				  "interrupts, re-enabling\n");
-			i915_driver_irq_preinstall(ring->dev);
-			i915_driver_irq_postinstall(ring->dev);
+			ring->dev->driver->irq_preinstall(ring->dev);
+			ring->dev->driver->irq_postinstall(ring->dev);
 		}
 
 		trace_i915_gem_request_wait_begin(ring, seqno);