ARM: EXYNOS: Remove setup-i2c0.c

Now since SAMSUNG_ATAGS is no longer selected for ARCH_EXYNOS, we can
safely remove the remaining setup code.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>