mmc: sdhci-tegra: Drop the use of sdhci_pltfm_free()

mmc: sdhci-tegra: 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.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/cee82eaad0392838fbe1fab8e2301e680d34c0c5.1749127796.git.zhoubinbin@loongson.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>