i2c: xilinx: Fix i2c checkpatch warnings

Code changes to fix checkpatch warnings listed below.
- WARNING: please, no space before tabs
- WARNING: quoted string split across lines

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>