dtoc: Add support for 32 or 64-bit addresses

When using 32-bit addresses dtoc works correctly. For 64-bit addresses it
does not since it ignores the #address-cells and #size-cells properties.

Update the tool to use fdt64_t as the element type for reg properties when
either the address or size is larger than one cell. Use the correct value
so that C code can obtain the information from the device tree easily.

Alos create a new type, fdt_val_t, which is defined to either fdt32_t or
fdt64_t depending on the word size of the machine. This type corresponds
to fdt_addr_t and fdt_size_t. Unfortunately we cannot just use those types
since they are defined to phys_addr_t and phys_size_t which use
'unsigned long' in the 32-bit case, rather than 'unsigned int'.

Add tests for the four combinations of address and size values (32/32,
64/64, 32/64, 64/32). Also update existing uses for rk3399 and rk3368
which now need to use the new fdt_val_t type.

Signed-off-by: Simon Glass <sjg@chromium.org>

Suggested-by: Heiko Stuebner <heiko@sntech.de>
Reported-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Kever Yang <kever.yang@rock-chips.com>