drm/mediatek: mtk_dsi: Remove unnecessary print function dev_err()

The print function dev_err() is redundant because platform_get_irq()
already prints an error.

Eliminate the follow coccicheck warning:
./drivers/gpu/drm/mediatek/mtk_dsi.c:1092:2-9: line 1092 is redundant
because platform_get_irq() already prints an error

Link: https://patchwork.kernel.org/project/linux-mediatek/patch/[e-mail]/
Reported-by: Abaci Robot <[e-mail]>
Signed-off-by: Yang Li <[e-mail]>
Signed-off-by: Chun-Kuang Hu <[e-mail]>

drivers/gpu/drm/mediatek/mtk_dsi.c

···
 
 	irq_num = platform_get_irq(pdev, 0);
 	if (irq_num < 0) {
-		dev_err(&pdev->dev, "failed to get dsi irq_num: %d\n", irq_num);
 		ret = irq_num;
 		goto err_unregister_host;
 	}