dtc: Remove obsolete check_properties() function

[Jon Loeliger]

So, like, the other day David Gibson mumbled:
> After the last couple of patches converting various old-style semantic
> checks to the new framework, the only thing that the old-style
> check_properties() function still checks is that the size of "reg"
> properties is a multiple of the cell size.
> 
> This patch removes check_properties() and all related code and data.
> The check on the size of reg properties is folded into the existing
> check for the format of "reg" properties (still old-style for the time
> being).
> 
> Signed-off-by: David Gibson <david at gibson.dropbear.id.au>

Applied.

jdl