mmc: sdhci-pci-gli: Improve GL9763E L1 entry delay to increase battery life

For GL9763E, although there is the best performance at the maximum delay.
Change the value to 20us in order to have better power consumption.
This change may reduce the maximum performance by 10%.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Link: https://lore.kernel.org/r/20210407093816.8863-1-benchuanggli@gmail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>