mmc: sdhci-st: drop of_match_ptr from of_device_id table

mmc: sdhci-st: drop of_match_ptr from of_device_id table

The driver can match only via the DT table so the table should be always
used and the of_match_ptr does not have any sense (this also allows ACPI
matching via PRP0001, even though it is not relevant here).  This fixes
compile warning (!CONFIG_OF on x86_64):

    drivers/mmc/host/sdhci-st.c:512:34: warning:
        ‘st_sdhci_match’ defined but not used [-Wunused-const-variable=]

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201120162344.485921-2-krzk@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>