pmdomain: mediatek: Handle SoCs with inverted SRAM power-down bits

pmdomain: mediatek: Handle SoCs with inverted SRAM power-down bits

Some SoCs, and even some subsystems in the same SoC, may have the
logic for SRAM power-down inverted, as in, setting the bit means
"power down" and unsetting means "power up": this is because some
hardware subsystems use this as a power-lock indication and some
use this as a power down one (for example, usually, the modem ss
has it inverted!).

In preparation for adding support for power domains with inverted
SRAM_PDN bits, add a new MTK_SCPD_SRAM_PDN_INVERTED flag and check
for it in scpsys_sram_enable() and scpsys_sram_disable().

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/20250805074746.29457-6-angelogioacchino.delregno@collabora.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>