exynos: pinmux: fix the gpio names for exynos4x12 mmc

This change fixes the bad gpio configuration for the exynos dwmmc.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Beomho Seo <beomho.seo@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>