clk: mediatek: clk-mt8192: Migrate topckgen to mtk_clk_simple_probe()

Since the common simple probe function for MediaTek clock drivers can
now register the MFG MUX notifier, it's possible to migrate MT8192's
topckgen to that, allowing for some code size reduction.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: Miles Chen <miles.chen@mediatek.com>
Link: https://lore.kernel.org/r/20230120092053.182923-20-angelogioacchino.delregno@collabora.com


Tested-by: Mingming Su <mingming.su@mediatek.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>