drm/i915: Separate sideband declarations to intel_sideband.h

Split the sideback declarations out of the ginormous i915_drv.h

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190426081725.31217-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_sysfs.c

@@ -29,7 +29,9 @@
 #include <linux/module.h>
 #include <linux/stat.h>
 #include <linux/sysfs.h>
+
 #include "intel_drv.h"
+#include "intel_sideband.h"
 #include "i915_drv.h"
 
 static inline struct drm_i915_private *kdev_minor_to_i915(struct device *kdev)