of/fdt: Add endianness helper function for early init code

Provide a libfdt-based equivalent for of_device_is_big_endian(), suitable
for use in the early_init_* functions.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 0ff360d..587ee50 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -33,6 +33,8 @@
 extern int of_fdt_is_compatible(const void *blob,
 				unsigned long node,
 				const char *compat);
+extern bool of_fdt_is_big_endian(const void *blob,
+				 unsigned long node);
 extern int of_fdt_match(const void *blob, unsigned long node,
 			const char *const *compat);
 extern void of_fdt_unflatten_tree(unsigned long *blob,