arm64: dts: qcom: x1e80100-lenovo-yoga-slim7x: add retimers, dp altmode support

comparing with CRD and other dts for a more complete support of the 7X
only retimers, gpios, regulators, dp outputs

Tested-by: Rob Clark <robdclark@gmail.com>
Tested-by: Jos Dehaes <jos.dehaes@gmail.com>
Signed-off-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250417-slim7x-retimer-v2-1-dbe2dd511137@oldschoolsolutions.biz
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

Author: jglathe