powerpc: Add del_node() for early boot code to prune inapplicable devices.

Some platforms have variants that can share most of a flat device tree but need
a few devices selectively pruned at boot time. This adds del_node() to ops.h
to allow access to the existing fdt_del_node().

Signed-off-by: Mike Ditto <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

arch/powerpc/boot/libfdt-wrapper.c

···
 	return check_err(rc);
 }
 
+static int fdt_wrapper_del_node(const void *devp)
+{
+	return fdt_del_node(fdt, devp_offset(devp));
+}
+
 static void *fdt_wrapper_get_parent(const void *devp)
 {
 	return offset_devp(fdt_parent_offset(fdt, devp_offset(devp)));
···
 	dt_ops.create_node = fdt_wrapper_create_node;
 	dt_ops.find_node_by_prop_value = fdt_wrapper_find_node_by_prop_value;
 	dt_ops.find_node_by_compatible = fdt_wrapper_find_node_by_compatible;
+	dt_ops.del_node = fdt_wrapper_del_node;
 	dt_ops.get_path = fdt_wrapper_get_path;
 	dt_ops.finalize = fdt_wrapper_finalize;
 

arch/powerpc/boot/ops.h

···
 			const int buflen);
 	int	(*setprop)(const void *phandle, const char *name,
 			const void *buf, const int buflen);
+	int (*del_node)(const void *phandle);
 	void *(*get_parent)(const void *phandle);
 	/* The node must not already exist. */
 	void *(*create_node)(const void *parent, const char *name);
···
 		return dt_ops.setprop(devp, name, buf, strlen(buf) + 1);
 
 	return -1;
+}
+
+static inline int del_node(const void *devp)
+{
+	return dt_ops.del_node ? dt_ops.del_node(devp) : -1;
 }
 
 static inline void *get_parent(const char *devp)