mmc: sdhci-brcmstb: Use sdhci_pltfm_remove()

mmc: sdhci-brcmstb: Use sdhci_pltfm_remove()

Use sdhci_pltfm_remove() instead of sdhci_pltfm_unregister() so that
devm_clk_get_optional_enabled() can be used for pltfm_host->clk.

This has the side effect that the order of operations on the error path
and remove path is not the same as it was before, but should be safe
nevertheless.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230811130351.7038-4-adrian.hunter@intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>