dmaengine: sh: rz-dmac: Drop the update of channel->chctrl with CHCTRL_SETEN

dmaengine: sh: rz-dmac: Drop the update of channel->chctrl with CHCTRL_SETEN

The CHCTRL_SETEN bit is explicitly set in rz_dmac_enable_hw(). Updating
struct rz_dmac_chan::chctrl with this bit in
rz_dmac_prepare_desc_for_memcpy() and rz_dmac_prepare_descs_for_slave_sg()
is unnecessary in the current code base. Moreover, it conflicts with the
configuration sequence that will be used for cyclic DMA channels during
suspend to RAM. Cyclic DMA support will be introduced in subsequent
commits.

This is a preparatory commit for cyclic DMA suspend to RAM support.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
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/20260526084710.3491480-12-claudiu.beznea@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>