sparc64: Add generic interface for registering a dimm printing handler.

The way to do this varies by platform type and the exact memory
controller the cpu uses.

For Spitfire cpus we currently just use prom_getunumber() and hope
that works.

For Cheetah cpus we have a memory controller driver that can
compute this information.

Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/memctrl.h

@@ -0,0 +1,9 @@
+#ifndef _SPARC_MEMCTRL_H
+#define _SPARC_MEMCTRL_H
+
+typedef int (*dimm_printer_t)(int synd_code, unsigned long paddr, char *buf, int buflen);
+
+int register_dimm_printer(dimm_printer_t func);
+void unregister_dimm_printer(dimm_printer_t func);
+
+#endif /* _SPARC_MEMCTRL_H */