mmc: dw_mmc: remove dw_mci_of_cd_gpio/wp_gpio()

If mmc_of_parse() is used, dw_mci_of_get_cd_gpio/wp_gpio didn't need.
Already implemented into mmc_of_parse().

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>