ppc/pegasos2: Fix naming of device tree nodes

ppc/pegasos2: Fix naming of device tree nodes

The board firmware names devices by their class so match that for
common devices. Also make sure the /rtas node has a name. This is
needed because VOF otherwise does not include it in results got by
nextprop which is how AmigaOS queries it and fails if no name property
is found.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-ID: <808ade37aa141563d1ee349254151672bf7a5d59.1689725688.git.balaton@eik.bme.hu>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>