dtoc: Output nodes in order

dtoc: Output nodes in order

Previously we had to worry about nodes being output before those that they
depended on, thus causing build errors.  So the current algorithm is
careful to output nodes in the right order.

We now use a different method for outputting phandles that does not
involve pointers. Also we plan to add a 'declarations' header file to
declare all drivers as 'extern'.

Update the code to drop the dependency checking and output in a simple
loop. This makes the output easier to follow since drivers are in order of
thier indices (0, 1, ...), which is also the order it appears in in the
linker list.

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