[POWERPC] Fix of_i2c include for module compilation

Remove #ifdef CONFIG_OF_I2C as this breaks module compilation.
Drivers using this header should depend on OF_I2C anyways, so
there's no need to make this conditional.

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/linux/of_i2c.h

@@ -14,11 +14,7 @@
 
 #include <linux/i2c.h>
 
-#ifdef CONFIG_OF_I2C
-
 void of_register_i2c_devices(struct i2c_adapter *adap,
 			     struct device_node *adap_node);
 
-#endif /* CONFIG_OF_I2C */
-
 #endif /* __LINUX_OF_I2C_H */