Much needed refinement of mpc5200 device tree binding specifications.

Short list:
- drop mpc52xx designator; only two supported chips exist, 5200 and 5200b.
  It's premature to refer to them as '52xx'.
- Specify optional 'model' and 'revision' properties in the soc5200 node
- Specify reqiured 'cell-index' property to identify between multiple SOC
  devices of the same type.  (Useful for arbitrating shared register access)
- Specify optional 'port-number' property for adjusting the logical serial
  port assignments.
- Specify optional 'has-wdt' property for gpt0 node.
- Add system-frequency property to soc5200 node
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Documentation-only change.  The 5200 device tree layout has not yet
stablized, so nobody should depend on the layout of the tree.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NSylvain Munaut <tnt@246tNt.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

This corrects the documented interface for mpc52xx device trees.
Sound devices should be using 'sound' for the device_type field, not
the type of sound interface.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NSylvain Munaut <tnt@246tNt.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NSylvain Munaut <tnt@246tNt.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>