clk: meson: remove clk input helper

clk: meson: remove clk input helper

The clk input function which allows clock controllers to register a bypass
clock from a clock producer is no longer needed anymore since meson clock
controllers have migrated to a new parent allocation method.

Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>