ARM: dts: Correct pin configuration of SD 4 for exynos4x12-pinctrl

This patch corrects the pin function value of sd4_bus8
from 3 to 4. This is verified on origen board for testing
eMMC on dw_mci controller.

Signed-off-by: Shirish S <s.shirish@samsung.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>