mmc: sdhci-pci: remove PCI PM functions in suspend/resume callback

It is not required (in fact it even is not recommended) that a PCI
driver's suspend() callback save the standard configuration registers
of the device, prepare it for waking up the system, or put it into a
low-power state.  All of these operations can very well be taken
care of by the PCI subsystem, without the driver's participation. Thus
remove these PCI functions.

For the device which has wake up capability, use device_init_wakeup to
init the wake up capability so that PCI core will help to enable the wakeup
for it.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>