ARM: dts: Fix pull setting in sd4_width8 pin group for exynos4x12

The group has the samsung,pin-pud property set to 4, which is not a
correct value. This patch fixes this by replacing it with 3, which is
the correct value for pull-up.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>