mmc: meson-mx-sdhc: Drop unused MESON_SDHC_NUM_BUILTIN_CLKS macro

Remove MESON_SDHC_NUM_BUILTIN_CLKS because it is not used anywhere in
the driver.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20211219153442.463863-3-martin.blumenstingl@googlemail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>