mmc: sdhci-pci: add UHS-II support framework

This patch prepares for adding UHS-II support at a specific UHS-II
capable sdhci-pci controller, GL9755 for now.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Message-ID: <20241018105333.4569-15-victorshihgli@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>