of: merge of_attach_node() & of_detach_node()

Merge common code between PowerPC and Microblaze

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 462825e..7cecc8f 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -2,6 +2,10 @@
 	bool
 	depends on OF
 
+config OF_DYNAMIC
+	def_bool y
+	depends on OF && PPC_OF
+
 config OF_DEVICE
 	def_bool y
 	depends on OF && (SPARC || PPC_OF || MICROBLAZE)