net: pcs: rzn1-miic: remove unused struct members and use miic variable

Remove unused bulk clocks struct from the miic state and use an already
existing miic variable in miic_config().

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20230208161249.329631-1-clement.leger@bootlin.com


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