video: mxsfb: add support for i.MXRT

Add support for i.MXRT by adding CONFIG_IMXRT in register structure and
adding .compatible = "fsl,imxrt-lcdif".

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index f21f824..6826ba3 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -440,6 +440,7 @@
 	{ .compatible = "fsl,imx23-lcdif" },
 	{ .compatible = "fsl,imx28-lcdif" },
 	{ .compatible = "fsl,imx7ulp-lcdif" },
+	{ .compatible = "fsl,imxrt-lcdif" },
 	{ /* sentinel */ }
 };