exynos5: enable dm i2c

This patch enables CONFIG_DM_I2C and also CONFIG_DM_I2C_COMPAT.
The last one should be removed when all the i2c peripheral
drivers will use dm i2c framework.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Cc: Akshay Saraswat <akshay.s@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Simon Glass <sjg@chromium.org>