Set SDHCI VMMC/VQMMC to <=2v96 and allow load setting by the SDHCI
driver, as required by this use case.

Configure the SD Card Detect pin, enable the SDHCI2 controller and
assign it the aforementioned regulators.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221114105043.36698-4-konrad.dybcio@linaro.org