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

mmc: sdhci-npcm: 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: Avi Fishman <avifishman70@gmail.com>
Cc: Tomer Maimon <tmaimon77@gmail.com>
Cc: Tali Perry <tali.perry1@gmail.com>
Cc: Patrick Venture <venture@google.com>
Cc: Nancy Yuen <yuenn@google.com>
Cc: Benjamin Fair <benjaminfair@google.com>
Cc: openbmc@lists.ozlabs.org
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Link: https://lore.kernel.org/r/08f9a1f6c2a1ad908baaf01623cd9670bf540aa3.1749127796.git.zhoubinbin@loongson.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>