dtc: Migrate "one cell" checks to new framework

[Jon Loeliger]

So, like, the other day David Gibson mumbled:
> This patch converts to the new tree checking framework those checks
> which verify that certain properties (#address-cells and #size-cells)
> are exactly one cell in size, when present.
> 
> We also drop the old-style check for "linux,phandle" being one cell,
> since that is already implied in the the existing new-style checks on
> the linux,phandle property.
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

jdl