PnvChipClass, PnvChip, Pnv8Chip, Pnv9Chip, and Pnv10Chip are defined
in pnv.h.  Many users of the header don't actually need them.  One
instance is this inclusion loop: hw/ppc/pnv_homer.h includes
hw/ppc/pnv.h for typedef PnvChip, and vice versa for struct PnvHomer.

Similar structs live in their own headers: PnvHomerClass and PnvHomer
in pnv_homer.h, PnvLpcClass and PnvLpcController in pci_lpc.h,
PnvPsiClass, PnvPsi, Pnv8Psi, Pnv9Psi, Pnv10Psi in pnv_psi.h, ...

Move PnvChipClass, PnvChip, Pnv8Chip, Pnv9Chip, and Pnv10Chip to new
pnv_chip.h, and adjust include directives.  This breaks the inclusion
loop mentioned above.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20221222104628.659681-2-armbru@redhat.com>