drm/i915: Include engine->mmio_base in the debug dump

Some IGT would like to know the mmio address of each engine so make it
available.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813215707.14703-1-chris@chris-wilson.co.uk

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

@@ -1404,6 +1404,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
 	}
 	spin_unlock_irqrestore(&engine->active.lock, flags);
 
+	drm_printf(m, "\tMMIO base:  0x%08x\n", engine->mmio_base);
 	wakeref = intel_runtime_pm_get_if_in_use(&engine->i915->runtime_pm);
 	if (wakeref) {
 		intel_engine_print_registers(engine, m);