mmc: core: clean up duplicate macros

Clean up the duplicate macros:
mmc_sd_card_uhs -> mmc_card_uhs
mmc_sd_card_set_uhs -> mmc_card_set_uhs

Signed-off-by: Jackey Shen <jackey.shen@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>