drm/amdgpu: Add compile flag for securedisplay

Add compile flag CONFIG_DEBUG_FS to clear the warning:
unused variable 'amdgpu_securedisplay_debugfs_ops'
Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -86,6 +86,8 @@ void psp_prep_securedisplay_cmd_buf(struct psp_context *psp, struct securedispla
 	(*cmd)->cmd_id = command_id;
 }
 
+#if defined(CONFIG_DEBUG_FS)
+
 static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __user *buf,
 		size_t size, loff_t *pos)
 {
@@ -162,6 +164,8 @@ static const struct file_operations amdgpu_securedisplay_debugfs_ops = {
 	.llseek = default_llseek
 };
 
+#endif
+
 void amdgpu_securedisplay_debugfs_init(struct amdgpu_device *adev)
 {
 #if defined(CONFIG_DEBUG_FS)