of/flattree: merge find_flat_dt_string and initial_boot_params

Merge common code between Microblaze and PowerPC.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index bbd8327..f39c927 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -111,6 +111,7 @@
 
 config OF
 	def_bool y
+	select OF_FLATTREE
 
 config PROC_DEVICETREE
 	bool "Support for device tree in /proc"