drm/i915: extract i915_sysfs.h from i915_drv.h

It used to be handy that we only had a couple of headers, but over time
i915_drv.h has become unwieldy. Extract declarations to a separate
header file corresponding to the implementation module, clarifying the
modularity of the driver.

Ensure the new header is self-contained, and do so with minimal further
includes, using forward declarations as needed. Include the new header
only where needed, and sort the modified include directives while at it
and as needed.

No functional changes.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/2276d0401a52389fe3aafe7e62b07a198353045e.1565271681.git.jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index cd5a17d..2bc3c6c 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -70,6 +70,7 @@
 #include "i915_irq.h"
 #include "i915_perf.h"
 #include "i915_query.h"
+#include "i915_sysfs.h"
 #include "i915_trace.h"
 #include "i915_vgpu.h"
 #include "intel_csr.h"
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0e422cc..0913683 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2503,10 +2503,6 @@
 int i915_save_state(struct drm_i915_private *dev_priv);
 int i915_restore_state(struct drm_i915_private *dev_priv);
 
-/* i915_sysfs.c */
-void i915_setup_sysfs(struct drm_i915_private *dev_priv);
-void i915_teardown_sysfs(struct drm_i915_private *dev_priv);
-
 /* intel_device_info.c */
 static inline struct intel_device_info *
 mkwrite_device_info(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 013c80aa..d8a3b18 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -31,6 +31,7 @@
 #include <linux/sysfs.h>
 
 #include "i915_drv.h"
+#include "i915_sysfs.h"
 #include "intel_pm.h"
 #include "intel_sideband.h"
 
diff --git a/drivers/gpu/drm/i915/i915_sysfs.h b/drivers/gpu/drm/i915/i915_sysfs.h
new file mode 100644
index 0000000..41afd43
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_sysfs.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef __I915_SYSFS_H__
+#define __I915_SYSFS_H__
+
+struct drm_i915_private;
+
+void i915_setup_sysfs(struct drm_i915_private *i915);
+void i915_teardown_sysfs(struct drm_i915_private *i915);
+
+#endif /* __I915_SYSFS_H__ */