phy: rockchip: naneng-combphy: Consolidate SSC configuration

phy: rockchip: naneng-combphy: Consolidate SSC configuration

The PCIe SSC configuration for the RK3588 and RK3576 SoCs required
additional tuning which is missing. When adding these same SSC
configurations for both of these two SoCs, as well as upcoming
platforms, it's obvious the SSC setup code was largely duplicated
across the platform-specific configuration functions. This becomes
harder to maintain as more platforms are added.

So extract the common SSC logic into a shared helper function,
rk_combphy_common_cfg_ssc(). This cleans up the per-platform drivers
and centralizes the standard configuration as possible.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Link: https://patch.msgid.link/1777251433-110466-1-git-send-email-shawn.lin@rock-chips.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>