drm/mediatek: aal: Add kerneldoc for struct mtk_disp_aal

The kerneldoc for struct mtk_disp_aal is missing: write one and
document this structure.

Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231012095736.100784-15-angelogioacchino.delregno@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

Author: AngeloGioacchino Del Regno

drivers/gpu/drm/mediatek/mtk_disp_aal.c

@@ -35,6 +35,13 @@ struct mtk_disp_aal_data {
 	bool has_gamma;
 };
 
+ /**
+  * struct mtk_disp_aal - Display Adaptive Ambient Light driver structure
+  * @clk:      clock for DISP_AAL controller
+  * @regs:     MMIO registers base
+  * @cmdq_reg: CMDQ Client register
+  * @data:     platform specific data for DISP_AAL
+  */
 struct mtk_disp_aal {
 	struct clk *clk;
 	void __iomem *regs;