powerpc/macio: Add devres support to macio_device

This adds some basic devres support. When enabled via macio_enable_devres()
resources requested by drivers will be automatically released.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/macio.h b/arch/powerpc/include/asm/macio.h
index 079c06e..2b7b392 100644
--- a/arch/powerpc/include/asm/macio.h
+++ b/arch/powerpc/include/asm/macio.h
@@ -78,6 +78,8 @@
 	return res->end - res->start + 1;
 }
 
+extern int macio_enable_devres(struct macio_dev *dev);
+
 extern int macio_request_resource(struct macio_dev *dev, int resource_no, const char *name);
 extern void macio_release_resource(struct macio_dev *dev, int resource_no);
 extern int macio_request_resources(struct macio_dev *dev, const char *name);