drm: exynos: Use proper macro definition for HDMI_I2S_PIN_SEL_1

Bit field [2:0] of HDMI_I2S_PIN_SEL_1 corresponds to SDATA_0,
not SDATA_2. This patch removes redefinition of HDMI_I2S_SEL_DATA2
constant and adds missing HDMI_I2S_SEL_DATA0.
The value of bit field selecting SDATA_1 (pin_sel_3) is also changed,
so it is 3 as suggested in the Exynos TRMs.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>