drm/i915: Use chipset-specific irq installers

Konstantin Belousov pointed out that 4697995b98417 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: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c6389de..e81dbe5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2080,8 +2080,8 @@
 		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);