dw-i2c: correct I2C FIFO size to 256 bytes

dw-i2c: correct I2C FIFO size to 256 bytes

BZ: 37123

I2C FIFO is set as 32 bytes in current driver. It will impact our
customer touchscreen driver implementation. Based on silicon team
feedback, need to correct I2C FIFO size to 256 bytes.
Meanwhile, correct one log description.

Change-Id: Icb07a9251cf24eeda76b1cbbf9f1d6ac83c506c5
Signed-off-by: Li, Ning <ning.li@intel.com>
Reviewed-on: http://android.intel.com:8080/49305
Reviewed-by: Yang, Bin <bin.yang@intel.com>
Reviewed-by: Du, Alek <alek.du@intel.com>
Reviewed-by: Chen, Jie D <jie.d.chen@intel.com>
Tested-by: Tang, HaifengX <haifengx.tang@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>