media: dt-bindings: imx7-csi: add i.MX6UL/L support

Document "fsl,imx6ul-csi" entry.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/imx7-csi.txt

@@ -9,7 +9,7 @@ to connect directly to external CMOS image sensors.
 
 Required properties:
 
-- compatible    : "fsl,imx7-csi";
+- compatible    : "fsl,imx7-csi" or "fsl,imx6ul-csi";
 - reg           : base address and length of the register set for the device;
 - interrupts    : should contain CSI interrupt;
 - clocks        : list of clock specifiers, see