phy: rockchip: naneng-combphy: Support rk3588

Add support for rk3588 phy variant.
The PHY clock is fixed at 100MHz.

Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
[kever.yang@rock-chips.com: update pcie pll parameters]
Co-developed-by: Kever Yang <kever.yang@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
[eugen.hristev@collabora.com: squashed, tidy up]
Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>