of/flattree: make of_fdt.h safe to unconditionally include.

If CONFIG_OF_FLATTREE is not set, then don't process the body of
linux/of_fdt.h
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

include/linux/of_fdt.h

@@ -57,6 +57,7 @@ struct boot_param_header {
 	__be32	dt_struct_size;		/* size of the DT structure block */
 };
 
+#if defined(CONFIG_OF_FLATTREE)
 /* TBD: Temporary export of fdt globals - remove when code fully merged */
 extern int __initdata dt_root_addr_cells;
 extern int __initdata dt_root_size_cells;
@@ -98,6 +99,7 @@ extern int early_init_dt_scan_root(unsigned long node, const char *uname,
 /* Other Prototypes */
 extern void unflatten_device_tree(void);
 extern void early_init_devtree(void *);
+#endif /* CONFIG_OF_FLATTREE */
 
 #endif /* __ASSEMBLY__ */
 #endif /* _LINUX_OF_FDT_H */