drm: xlnx: dptx: Change the VTC sub-core offset address

commit ac5749fd7c3f062e7705b80bbed937a2df8b648a from
https://github.com/Xilinx/linux-xlnx.git

 xlnx_rebase_v5.15

VTC sub-core offset is now changed in DP Tx SS and IP Version has been
updated to 3.1. Now we get VTC offset from device tree instead

Signed-off-by: Rajesh Gugulothu <rajesh.gugulothu@amd.com>
Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
State: pending
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>