fdt: Add device tree memory bindings

Support a default memory bank, specified in reg, as well as
board-specific memory banks in subtree board-id nodes.

This allows memory information to be provided in the device tree,
rather than hard-coded in, which will make it simpler to handle
similar devices with different memory banks, as the board-id values
or masks can be used to match devices.

Signed-off-by: Michael Pratt <mpratt@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 2d451f8..0fd4900 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -52,6 +52,7 @@
 	unsigned long env_has_init;	/* Bitmask of boolean of struct env_location offsets */
 	int env_load_location;
 
+	unsigned long ram_base;		/* Base address of RAM used by U-Boot */
 	unsigned long ram_top;		/* Top address of RAM used by U-Boot */
 	unsigned long relocaddr;	/* Start address of U-Boot in RAM */
 	phys_size_t ram_size;		/* RAM size */