net: fs_enet: Remove unused fields in fs_platform_info struct

Since commit 3dd82a1e ("[POWERPC] CPM: Always use new binding.")
many fields of fs_platform_info structure are not used anymore.

Remove them.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/2e584fcd75e21a0f7e7d5f942eebdc067b2f82f9.1691155346.git.christophe.leroy@csgroup.eu


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