Documentation: powerpc/fsl: Update compatible for l2cache binding

List all the current valid compatible strings for the l2cache binding.
This should stop checkpatch.pl from complaining and will hopefully save
someone from having to debug a typo in their dts.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Documentation/devicetree/bindings/powerpc/fsl/l2cache.txt

@@ -5,8 +5,46 @@ The cache bindings explained below are ePAPR compliant
 
 Required Properties:
 
-- compatible	: Should include "fsl,chip-l2-cache-controller" and "cache"
-		  where chip is the processor (bsc9132, npc8572 etc.)
+- compatible	: Should include one of the following:
+		  "fsl,8540-l2-cache-controller"
+		  "fsl,8541-l2-cache-controller"
+		  "fsl,8544-l2-cache-controller"
+		  "fsl,8548-l2-cache-controller"
+		  "fsl,8555-l2-cache-controller"
+		  "fsl,8568-l2-cache-controller"
+		  "fsl,b4420-l2-cache-controller"
+		  "fsl,b4860-l2-cache-controller"
+		  "fsl,bsc9131-l2-cache-controller"
+		  "fsl,bsc9132-l2-cache-controller"
+		  "fsl,c293-l2-cache-controller"
+		  "fsl,mpc8536-l2-cache-controller"
+		  "fsl,mpc8540-l2-cache-controller"
+		  "fsl,mpc8541-l2-cache-controller"
+		  "fsl,mpc8544-l2-cache-controller"
+		  "fsl,mpc8548-l2-cache-controller"
+		  "fsl,mpc8555-l2-cache-controller"
+		  "fsl,mpc8560-l2-cache-controller"
+		  "fsl,mpc8568-l2-cache-controller"
+		  "fsl,mpc8569-l2-cache-controller"
+		  "fsl,mpc8572-l2-cache-controller"
+		  "fsl,p1010-l2-cache-controller"
+		  "fsl,p1011-l2-cache-controller"
+		  "fsl,p1012-l2-cache-controller"
+		  "fsl,p1013-l2-cache-controller"
+		  "fsl,p1014-l2-cache-controller"
+		  "fsl,p1015-l2-cache-controller"
+		  "fsl,p1016-l2-cache-controller"
+		  "fsl,p1020-l2-cache-controller"
+		  "fsl,p1021-l2-cache-controller"
+		  "fsl,p1022-l2-cache-controller"
+		  "fsl,p1023-l2-cache-controller"
+		  "fsl,p1024-l2-cache-controller"
+		  "fsl,p1025-l2-cache-controller"
+		  "fsl,p2010-l2-cache-controller"
+		  "fsl,p2020-l2-cache-controller"
+		  "fsl,t2080-l2-cache-controller"
+		  "fsl,t4240-l2-cache-controller"
+		  and "cache".
 - reg		: Address and size of L2 cache controller registers
 - cache-size	: Size of the entire L2 cache
 - interrupts	: Error interrupt of L2 controller