ARM: MM: Add DT binding for Feroceon L2 cache

Instantiate the L2 cache from DT. Indicate in DT where the cache
control register is so that it is possible to enable/disable write
through on the CPU.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/include/asm/hardware/cache-feroceon-l2.h

@@ -9,3 +9,5 @@
  */
 
 extern void __init feroceon_l2_init(int l2_wt_override);
+extern int __init feroceon_of_init(void);
+