drm/rockchip: dw_hdmi_qp: Switch to phy_configure()

drm/rockchip: dw_hdmi_qp: Switch to phy_configure()

Stop relying on phy_set_bus_width() based workaround to setup the TMDS
character rate and, instead, use the recently introduced HDMI PHY
configuration API.  This is also a prerequisite to enable high color
depth and FRL support.

Additionally, move the logic to ->atomic_check() callback where the
current mode rate is already provided by the connector state.  As a
matter of fact this is actually necessary to ensure the link rate is
configured before VOP2 attempts to use the PHY PLL as a DCLK source in
vop2_crtc_atomic_enable().  The rationale is to restrict any changes of
the PHY rate via CCF and, instead, prefer the PHY configuration API for
this purpose.

Acked-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20251021-rk3588-10bpc-v3-3-3d3eed00a6db@collabora.com