mmc: sdhci-uhs2: add related functions to initialize the interface

UHS-II interface (related registers) will be initialized here. The
operations include mmc's uhs2_set_reg operations, mmc's uhs2_detect_init
operations, uhs2_[enable|disable]_clk operations. After detected the UHS-II
interface, the host's UHS-II capabilities will be set up here and
interrupts will also be enabled.

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: <20241018105333.4569-11-victorshihgli@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>