[POWERPC] i2c: OF helpers for the i2c API

This implements various helpers to support OF bindings for the i2c
API.

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 3354ad7..7c30531 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -7,3 +7,9 @@
 	depends on OF && PPC_OF && HAVE_GPIO_LIB
 	help
 	  OpenFirmware GPIO accessors
+
+config OF_I2C
+	def_bool y
+	depends on OF && I2C
+	help
+	  OpenFirmware I2C accessors