mmc: rename mmc_can_erase() to mmc_card_can_erase()

mmc: rename mmc_can_erase() to mmc_card_can_erase()

mmc_can_* functions sometimes relate to the card and sometimes to the host.
Make it obvious by renaming this function to include 'card'. Also, convert to
proper bool type while we are here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20250401095847.29271-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>