net: fs_enet: Don't include fs_enet_pd.h when not needed

Three platforms in arch/powerpc/platforms/8xx/ include fs_enet_pd.h
but don't use anything from it.

Remove the includes.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/de62ad1261a801c4a8ae4238bd4842ff278d2ddf.1691155347.git.christophe.leroy@csgroup.eu


Signed-off-by: Jakub Kicinski <kuba@kernel.org>