clk: mediatek: mux: Implement error handling in register API

The mux clk type registration function does not stop or return errors
if any clk failed to be registered, nor does it implement an error
handling path. This may result in a partially working device if any
step failed.

Make the register function return proper error codes, and bail out if
errors occur. Proper cleanup, i.e. unregister any clks that were
successfully registered, is done in the new error path.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220208124034.414635-25-wenst@chromium.org


Reviewed-by: Chun-Jie Chen <chun-jie.chen@mediatek.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>