Fixes the following W=1 kernel build warning(s):
 drivers/gpu/drm/radeon/vce_v2_0.c:111:6: warning: no previous prototype for ‘vce_v2_0_enable_mgcg’ [-Wmissing-prototypes]
 111 | void vce_v2_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: Sumit Semwal <sumit.semwal@linaro.org>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
 #include "radeon_audio.h"
 #include "radeon_ucode.h"
 #include "si.h"
+#include "vce.h"
 
 #define SH_MEM_CONFIG_GFX_DEFAULT \
        ALIGNMENT_MODE(SH_MEM_ALIGNMENT_MODE_UNALIGNED)
 MODULE_FIRMWARE("radeon/mullins_sdma.bin");
 
 static u32 cik_get_cu_active_bitmap(struct radeon_device *rdev, u32 se, u32 sh);
-extern void vce_v2_0_enable_mgcg(struct radeon_device *rdev, bool enable);
 static void cik_rlc_stop(struct radeon_device *rdev);
 static void cik_pcie_gen3_enable(struct radeon_device *rdev);
 static void cik_program_aspm(struct radeon_device *rdev);
 
 struct radeon_device;
 
 void vce_v1_0_enable_mgcg(struct radeon_device *rdev, bool enable);
+void vce_v2_0_enable_mgcg(struct radeon_device *rdev, bool enable);
 
 #endif                         /* __VCE_H__ */
 
 #include "radeon.h"
 #include "radeon_asic.h"
 #include "cikd.h"
+#include "vce.h"
 
 #define VCE_V2_0_FW_SIZE       (256 * 1024)
 #define VCE_V2_0_STACK_SIZE    (64 * 1024)