drm/radeon/si_dpm: Move 'vce_v1_0_enable_mgcg()'s prototype to shared header

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/radeon/vce_v1_0.c:102:6: warning: no previous prototype for ‘vce_v1_0_enable_mgcg’ [-Wmissing-prototypes]
 102 | void vce_v1_0_enable_mgcg(struct radeon_device *rdev, bool enable)
 | ^~~~~~~~~~~~~~~~~~~~

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/si_dpm.c

@@ -35,6 +35,7 @@
 #include "si_dpm.h"
 #include "si.h"
 #include "sid.h"
+#include "vce.h"
 
 #define MC_CG_ARB_FREQ_F0           0x0a
 #define MC_CG_ARB_FREQ_F1           0x0b
@@ -1721,8 +1722,6 @@ static const struct si_powertune_data powertune_data_hainan =
 	true
 };
 
-extern void vce_v1_0_enable_mgcg(struct radeon_device *rdev, bool enable);
-
 static int si_populate_voltage_value(struct radeon_device *rdev,
 				     const struct atom_voltage_table *table,
 				     u16 value, SISLANDS_SMC_VOLTAGE_VALUE *voltage);

drivers/gpu/drm/radeon/trinity_dpm.c

@@ -29,6 +29,7 @@
 #include "radeon_asic.h"
 #include "trinity_dpm.h"
 #include "trinityd.h"
+#include "vce.h"
 
 #define TRINITY_MAX_DEEPSLEEP_DIVIDER_ID 5
 #define TRINITY_MINIMUM_ENGINE_CLOCK 800
@@ -293,7 +294,6 @@ static const u32 trinity_override_mgpg_sequences[] =
 	0x00000204, 0x00000000,
 };
 
-extern void vce_v1_0_enable_mgcg(struct radeon_device *rdev, bool enable);
 static void trinity_program_clk_gating_hw_sequence(struct radeon_device *rdev,
 						   const u32 *seq, u32 count);
 static void trinity_override_dynamic_mg_powergating(struct radeon_device *rdev);

drivers/gpu/drm/radeon/vce.h

+/* vce.h -- Private header for radeon driver -*- linux-c -*-
+ *
+ * Copyright 2013 Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ */
+
+#ifndef __VCE_H__
+#define __VCE_H__
+
+struct radeon_device;
+
+void vce_v1_0_enable_mgcg(struct radeon_device *rdev, bool enable);
+
+#endif                         /* __VCE_H__ */

drivers/gpu/drm/radeon/vce_v1_0.c

@@ -30,6 +30,7 @@
 #include "radeon.h"
 #include "radeon_asic.h"
 #include "sid.h"
+#include "vce.h"
 
 #define VCE_V1_0_FW_SIZE	(256 * 1024)
 #define VCE_V1_0_STACK_SIZE	(64 * 1024)