mmc: sdhci-pci: Remove dead code (struct sdhci_pci_data et al)

mmc: sdhci-pci: Remove dead code (struct sdhci_pci_data et al)

The last user of this struct gone a couple of releases ago.
Besides that there were not so many users of this API for
more than 10 years:

1/ The one is Intel Merrifield, that had been added 2016-08-31
   by the commit 3976b0380b31 ("x86/platform/intel-mid: Enable
   SD card detection on Merrifield") and removed 2021-02-11 by
   the commit 4590d98f5a4f ("sfi: Remove framework for deprecated
   firmware").

2/ The other is Intel Sunrisepoint related, that had been added
   2015-02-06 by the commit e1bfad6d936d ("mmc: sdhci-pci: Add
   support for drive strength selection for SPT") and removed
   2017-03-20 by the commit 51ced59cc02e ("mmc: sdhci-pci: Use
   ACPI DSM to get driver strength for some Intel devices").

Effectively this is a revert of the commit 52c506f0bc72 ("mmc:
sdhci-pci: add platform data").

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20211014132613.27861-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>