drm/amdgpu: clean function declarations in amdgpu_ttm.c up

We get 2 warnings when building kernel with W=1:

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:985:5: warning: no previous prototype for 'amdgpu_ttm_init' [-Wmissing-prototypes]
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:1092:6: warning: no previous prototype for 'amdgpu_ttm_fini' [-Wmissing-prototypes]

In fact, both functions are declared in
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c, but should be declared in
a header file, thus can be recognized in other file.

So this patch moves the declarations into
drivers/gpu/drm/amd/amdgpu/amdgpu.h.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

@@ -2447,6 +2447,8 @@ void amdgpu_gtt_location(struct amdgpu_device *adev, struct amdgpu_mc *mc);
 void amdgpu_ttm_set_active_vram_size(struct amdgpu_device *adev, u64 size);
 u64 amdgpu_ttm_get_gtt_mem_size(struct amdgpu_device *adev);
 int amdgpu_ttm_global_init(struct amdgpu_device *adev);
+int amdgpu_ttm_init(struct amdgpu_device *adev);
+void amdgpu_ttm_fini(struct amdgpu_device *adev);
 void amdgpu_program_register_sequence(struct amdgpu_device *adev,
 					     const u32 *registers,
 					     const u32 array_size);

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -38,8 +38,6 @@
 #include "amdgpu_trace.h"
 
 
-int amdgpu_ttm_init(struct amdgpu_device *adev);
-void amdgpu_ttm_fini(struct amdgpu_device *adev);
 
 static u64 amdgpu_get_vis_part_size(struct amdgpu_device *adev,
 						struct ttm_mem_reg *mem)