mmc: sdhci-pci-gli: GL9767: Fix low power mode in the SD Express process

When starting the SD Express process, the low power negotiation mode will
be disabled, so we need to re-enable it after switching back to SD mode.

Fixes: 0e92aec2 ("mmc: sdhci-pci-gli: Add support SD Express card for GL9767")
Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Cc: stable@vger.kernel.org
Message-ID: <20241025060017.1663697-2-benchuanggli@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>