drm/amdgpu: remove redundant variable r and redundant return statement

There is a return statement that is not reachable and a variable that
is not used.  Remove them.

Addresses-Coverity: ("Structurally dead code")
Fixes: de7b45ba ("drm/amdgpu: cleanup creating BOs at fixed location (v2)")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1651,7 +1651,6 @@ static void amdgpu_ttm_fw_reserve_vram_fini(struct amdgpu_device *adev)
 static int amdgpu_ttm_fw_reserve_vram_init(struct amdgpu_device *adev)
 {
 	uint64_t vram_size = adev->gmc.visible_vram_size;
-	int r;
 
 	adev->fw_vram_usage.va = NULL;
 	adev->fw_vram_usage.reserved_bo = NULL;
@@ -1666,7 +1665,6 @@ static int amdgpu_ttm_fw_reserve_vram_init(struct amdgpu_device *adev)
 					  AMDGPU_GEM_DOMAIN_VRAM,
 					  &adev->fw_vram_usage.reserved_bo,
 					  &adev->fw_vram_usage.va);
-	return r;
 }
 
 /**