drm: xlnx: hdmi: Add max frl rate property

commit  7ef059ac4c2e35c0eadfcfa943f7ea0bd6bb9a8a from
https://github.com/Xilinx/linux-xlnx.git

 xlnx_rebase_v5.10

This patch adds maximum fixed link rate property to the driver.

Signed-off-by: Venkateshwar Rao Gannavarapu <venkateshwar.rao.gannavarapu@xilinx.com>
State: pending
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>