I2C: Modify the I2C driver for EXYNOS5

I2C: Modify the I2C driver for EXYNOS5

This patch modifies the S3C I2C driver to suppport EXYNOS5.
The cahnges made to driver are as follows:
        - I2C base address is passed as a parameter to many
        functions to avoid multiple #ifdef
        - Channel initialisation is moved to a commom funation
        as it is required by i2c_init.
        - Hardcoding for I2CCON_ACKGEN removed.
        - Replaced printf with debug.
        - Checkpatch issues resolved.
        - Pinmux setting will be done in board/samsung/smdk5250/smdk5250.c
        to avoid repeated setting of gpio lines, as it have multi bus support.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>