mmc: mtk-sd: Aggregate R/W for top_base iospace case where possible

mmc: mtk-sd: Aggregate R/W for top_base iospace case where possible

In case the controller uses the top_base iospace, most register
read/writes can be changed from multiple RWs to a single read
and a single write.

Where possible, and where it makes sense, aggregate the multiple
reads and writes to just one.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20250325110701.52623-5-angelogioacchino.delregno@collabora.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>