Sort the subnodes of the soc node to improve maintainability.
The sort key is the address on the bus with instances of the same
IP block grouped together and sorted alphabetically.

This patch should not introduce any functional change.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>