mmc: sdhci-pci: Do not use suspend/resume callbacks with runtime pm

Do not use suspend/resume callbacks with runtime pm. It doesn't make sense
and isn't being used, so remove.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ludovic Desroches <ludovic.desroches@microchip.com>