drm/bridge: analogix_dp: Reuse &link_train.training_lane[] to set DPCD DP_TRAINING_LA...

drm/bridge: analogix_dp: Reuse &link_train.training_lane[] to set DPCD DP_TRAINING_LANEx_SET

In analogix_dp_link_start(), &link_train.training_lane[] is used to
set phy PE/VS configurations, and buf[] is initialized with the same
values to set DPCD DP_TRAINING_LANEx_SET.

It makes sense to reuse &link_train.training_lane[] to set DPCD
DP_TRAINING_LANEx_SET, which can remove the redundant assignments
and make codes more concise.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://patch.msgid.link/20251111022103.1350183-1-damon.ding@rock-chips.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>