powerpc/5200: Trim cruft from device trees

Trim out obsolete/extraneous properties and tighten up some usage
conventions.  Changes include:
- removal of device_type properties
- removal of cell-index properties
- Addition of gpio-controller and #gpio-cells properties to gpio
  nodes
- Move common interrupt-parent property out of device nodes and
  into top level parent node.

This patch also include what looks to be just trivial editorial
whitespace/format changes, but there is real method in this
madness.  Editorial changes were made to keep the all the
mpc5200 board device trees as similar as possible so that diffs
between them only show the real differences between the boards.
The pcm030 device tree was most affected by this because many
of the comments had been changed from // to /* */ style and
some cell values where changed from decimal to hex format when
it was cloned from one of the other 5200 device trees.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>