char: xilinx_hwicap: Modernize driver probe

Rework Xilinx hwicap driver probe to use current best practices using
devres APIs, device_get_match_data(), and typed firmware property accessors.

There's no longer any non-DT probing, so CONFIG_OF ifdefs can be dropped.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20231006214228.337064-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>