mmc: sdhci_f_sdh30: Drop the use of sdhci_pltfm_free()

Since the devm_mmc_alloc_host() helper is already in use,
sdhci_pltfm_free() is no longer needed.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Link: https://lore.kernel.org/r/c216c46cb5aebe8e4598215428ace4440974c188.1749127796.git.zhoubinbin@loongson.cn


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