dmaengine: sh: rz-dmac: Add suspend to RAM support

dmaengine: sh: rz-dmac: Add suspend to RAM support

The Renesas RZ/G3S SoC supports a power saving mode in which power to most
of the SoC components is turned off, including the DMA IP. Add suspend to
RAM support to save and restore the DMA IP registers.

Cyclic DMA channels require special handling. Since they can be paused and
resumed during system suspend/resume, the driver restores additional
registers for these channels during the system resume phase. If a channel
was not explicitly paused during suspend, the driver ensures that it is
paused and resumed as part of the system suspend/resume flow.

Tested-by: John Madieu <john.madieu.xa@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Link: https://patch.msgid.link/20260526084710.3491480-16-claudiu.beznea@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>