clk: mediatek: Allow MT7622 clocks to be built as modules

Now that all drivers are using the simple probe mechanism change the
MT7622 clock drivers to tristate in Kconfig to allow module build.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20230306140543.1813621-42-angelogioacchino.delregno@collabora.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>