clk: mediatek: mt2712: Change Kconfig options to allow module build

clk: mediatek: mt2712: Change Kconfig options to allow module build

All of the mt2712 drivers have been converted to platform drivers!
Change the Kconfig options for all MT2712 clocks to tristate to allow
building all clock drivers as modules.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20230306140543.1813621-39-angelogioacchino.delregno@collabora.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>