mmc: core: Replace with already defined values for readability

[ Upstream commit e4272664

 ]

SD_ROCR_S18A is already defined and is used to check the rocr value, so
let's replace with already defined values for readability.

Signed-off-by: ChanWoo Lee <cw9316.lee@samsung.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220706004840.24812-1-cw9316.lee@samsung.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Stable-dep-of: e9233917

 ("mmc: core: Terminate infinite loop in SD-UHS voltage switch")
Signed-off-by: Sasha Levin <sashal@kernel.org>