Add initial support for the rk3588 PHY variant.
The lookup for the host-port reg inside the struct now does a do {} while()
instead of a while() {} in order to allow a first check for reg == 0.

Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Co-developed-by: Frank Wang <frank.wang@rock-chips.com>
Signed-off-by: Frank Wang <frank.wang@rock-chips.com>
Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>