mmc: sdhci-pxav2: add register workaround for PXA168 silicon bug

mmc: sdhci-pxav2: add register workaround for PXA168 silicon bug

The PXA168 has a documented silicon bug that results in a data abort
exception when accessing the SDHCI_HOST_VERSION register on SDH2 and
SDH4 through a 16-bit read. Implement the workaround described in the
errata, which performs a 32-bit read from a lower address instead. This
is safe to use on all four SDH peripherals.

Signed-off-by: Doug Brown <doug@schmorgal.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230116194401.20372-4-doug@schmorgal.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>