mmc: sdhci-esdhc-imx: Drop the use of sdhci_pltfm_free()

mmc: sdhci-esdhc-imx: 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: Haibo Chen <haibo.chen@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: imx@lists.linux.dev
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/9b9014749a9870a9cb3c2818fe9b38c013cb46ca.1749127796.git.zhoubinbin@loongson.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>