drm/i915: i915_mutex_interruptible() returns -EINTR

... so we handle that for i915_gem_fault() in the same manner as
ERESTARTSYS, or we send a SIGBUS to the faulting application.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem.c

@@ -1230,6 +1230,7 @@ out:
 		set_need_resched();
 	case 0:
 	case -ERESTARTSYS:
+	case -EINTR:
 		return VM_FAULT_NOPAGE;
 	case -ENOMEM:
 		return VM_FAULT_OOM;