drm/i915: Extract general GT interrupt handlers

i915_irq.c is large. It serves as the central dispatch and handler for
all of our device interrupts. Lets break it up by pulling out the GT
interrupt handlers.

Based on a patch by Chris Wilson.

Signed-off-by: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190811210633.18417-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Makefile

@@ -80,6 +80,7 @@ gt-y += \
 	gt/intel_engine_pm.o \
 	gt/intel_engine_user.o \
 	gt/intel_gt.o \
+	gt/intel_gt_irq.o \
 	gt/intel_gt_pm.o \
 	gt/intel_gt_pm_irq.o \
 	gt/intel_hangcheck.o \

drivers/gpu/drm/i915/gt/intel_breadcrumbs.c

@@ -35,9 +35,9 @@ static void irq_enable(struct intel_engine_cs *engine)
 		return;
 
 	/* Caller disables interrupts */
-	spin_lock(&engine->i915->irq_lock);
+	spin_lock(&engine->gt->irq_lock);
 	engine->irq_enable(engine);
-	spin_unlock(&engine->i915->irq_lock);
+	spin_unlock(&engine->gt->irq_lock);
 }
 
 static void irq_disable(struct intel_engine_cs *engine)
@@ -46,9 +46,9 @@ static void irq_disable(struct intel_engine_cs *engine)
 		return;
 
 	/* Caller disables interrupts */
-	spin_lock(&engine->i915->irq_lock);
+	spin_lock(&engine->gt->irq_lock);
 	engine->irq_disable(engine);
-	spin_unlock(&engine->i915->irq_lock);
+	spin_unlock(&engine->gt->irq_lock);
 }
 
 static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)