media: dt-bindings: media: Add Aspeed Video Engine binding documentation

Document the bindings.
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/aspeed-video.txt

+* Device tree bindings for Aspeed Video Engine
+
+The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs can
+capture and compress video data from digital or analog sources.
+
+Required properties:
+ - compatible:		"aspeed,ast2400-video-engine" or
+			"aspeed,ast2500-video-engine"
+ - reg:			contains the offset and length of the VE memory region
+ - clocks:		clock specifiers for the syscon clocks associated with
+			the VE (ordering must match the clock-names property)
+ - clock-names:		"vclk" and "eclk"
+ - resets:		reset specifier for the syscon reset associated with
+			the VE
+ - interrupts:		the interrupt associated with the VE on this platform
+
+Example:
+
+video-engine@1e700000 {
+    compatible = "aspeed,ast2500-video-engine";
+    reg = <0x1e700000 0x20000>;
+    clocks = <&syscon ASPEED_CLK_GATE_VCLK>, <&syscon ASPEED_CLK_GATE_ECLK>;
+    clock-names = "vclk", "eclk";
+    resets = <&syscon ASPEED_RESET_VIDEO>;
+    interrupts = <7>;
+};