mmc: sdhci-pci-o2micro: Fix Dell E5440 issue

Fix Dell E5440 when reboot Linux, can't find o2micro sd host chip issue.

Fixes: 01acf691 (mmc: sdhci-pci: add support of O2Micro/BayHubTech SD hosts)
Signed-off-by: Peter Guo <peter.guo@bayhubtech.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>