drm: xilinx: dp: Remove version from compatible string

Keeping the version in compatible strings isn't scalable, especially with
Soft IPs as releases are so frequent. Remove version from the Xilinx
DisplayPort compatible string.

Signed-off-by: Hyun Kwon <hyun.kwon@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>