dt-bindings: Fix incorrect 'reg' property sizes

The examples template is a 'simple-bus' with a size of 1 cell for
had between 2 and 4 cells which really only errors on I2C or SPI type
devices with a single cell.

The easiest fix in most cases is to change the 'reg' property to for 1 cell
address and size. In some cases with child devices having 2 cells, that
doesn't make sense so a bus node is needed.

Acked-by: Stephen Boyd <sboyd@kernel.org> # clk
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>