layerscape: rename Traverse boards along SoC lines

layerscape: rename Traverse boards along SoC lines

Upcoming product specification and branding changes mean that the names in tree do not accurately reflect released products.
To reduce any confusion, sort our boards by SoC family, e.g traverse-ls1043. Any future boards using Layerscape family SoC's
will be treated the same way, e.g Device/traverse-ls/lx/laXXXX.
The affected boards so far have only been available through OEM channels and those aren't using the provided sysupgrade.

Signed-off-by: Mathew McBride <matt@traverse.com.au>