exynos: i2c: Correct bug in pinmux selection

When driver model is not used the current code does not correctly select
the pinmux for the I2C bus. This bug was introduced by this commit:

8dfcbaa6 dm: i2c: s3c24x0: adjust to dm-i2c api

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Przemyslaw Marczak <p.marczak@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>