net: mdio: realtek-rtl9300: use command runner for read_c22()

net: mdio: realtek-rtl9300: use command runner for read_c22()

Convert the final missing read_c22() path to the new read enabled command
runner. Do it the same way as other implementations.

- bus calls otto_emdio_read_c22()
- this hands over to SoC specific otto_emdio_9300_read_c22()
- finally the registers are filled and the runner issued

With this cleanup remove the obsolete helper otto_emdio_wait_ready()

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20260527163449.1294961-5-markus.stockhausen@gmx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>