of: Only compile OF_DYNAMIC on PowerPC pseries and iseries

Only two architectures use the OF node reference counting and reclaim bits.
There is no need to compile it for the rest of the PowerPC platforms or for
any of the other architectures.  This patch makes iseries and pseries
select CONFIG_OF_DYNAMIC, and makes it default to off for everything else.

It is still safe to turn on CONFIG_OF_DYNAMIC on all architectures, it just
isn't necessary.

v2: Also select OF_DYNAMIC for PPC_CHROMA and MPC885ADS as reported by Michael
    Meuling

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Jimi Xenidis <jimix@pobox.com> (for PPC_CHROMA bug fix)
Cc: Rob Herring <rob.herring@calxeda.com>
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 268163d..6ea51dc 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -35,9 +35,10 @@
 config OF_PROMTREE
 	bool
 
+# Hardly any platforms need this.  It is safe to select, but only do so if you
+# need it.
 config OF_DYNAMIC
-	def_bool y
-	depends on PPC_OF
+	bool
 
 config OF_ADDRESS
 	def_bool y