of/promtree: make drivers/of/pdt.c no longer sparc-only

Clean up pdt.c:
 - make build dependent upon config OF_PROMTREE
 - #ifdef out the sparc-specific stuff
 - create pdt-specific header

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 491e9d6..a06c959 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -19,6 +19,7 @@
 	bool
 	default y
 	select OF
+	select OF_PROMTREE
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_ARCH_KGDB if !SMP || SPARC64