mmc: sdhci-sprd: Drop redundant cap flags

The MMC_CAP_ERASE and MMC_CAP_CMD23 flags are already being set in the
common sdhci_setup_host(). This makes it redundant to set them for
sdhci-sprd, so let's drop them.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200406113724.8504-1-ulf.hansson@linaro.org