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 might not be relevant here).  This
also fixes !CONFIG_OF error:

  drivers/input/keyboard/st-keyscan.c:251:34: error: ‘keyscan_of_match’ defined but not used [-Werror=unused-const-variable=]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230312131514.351603-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>