pmdomain: mediatek: Move ctl sequences out of power_on/off functions

pmdomain: mediatek: Move ctl sequences out of power_on/off functions

In preparation to support power domains of new SoCs and the modem
power domains for both new and already supported chips, move the
generic control power sequences out of the scpsys_power_on() and
scpsys_power_off() and put them in new scpsys_ctl_pwrseq_on(),
scpsys_ctl_pewseq_off() functions.

Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20250805074746.29457-7-angelogioacchino.delregno@collabora.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>