of: Stop naming platform_device using dcr address

There is now a way to ensure all platform devices get a unique name when
populated from the device tree, and the DCR_NATIVE code path is broken
anyway. PowerPC Cell (PS3) is the only platform that actually uses this
path.  Most likely nobody will notice if it is killed. Remove the code
and associated ugly #ifdef.

The user-visible impact of this patch is that any DCR device on Cell
will get a new name in the /sys/devices hierarchy.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>