mmc: sdhci-pci-gli: Reduce the SSC value at 205MHz for GL9750 and GL9755

The SSC value is 0xFFE7 at 205MHz and may be saturated. Reduce the SSC
value to 0x5A1D at 205MHz to reduce this situation for GL9750 and GL9755.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Link: https://lore.kernel.org/r/20220119075306.36262-1-benchuanggli@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>