clk: mediatek: clk-pll: Add ops for PLLs using set/clr regs and FENC

clk: mediatek: clk-pll: Add ops for PLLs using set/clr regs and FENC

MT8196 uses a combination of set/clr registers to control the PLL
enable state, along with a FENC bit to check the preparation status.
Add new set of PLL clock operations with support for set/clr enable and
FENC status logic.

Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Laura Nao <laura.nao@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>