fix error checking from i2c read return

Correct data type to capture i2c read return so error can be
detected correctly.

Tested:
Build and run the new code. No issues observed.

Signed-off-by: Zhikui Ren <zhikui.ren@intel.com>
Change-Id: Ie6bf9480f3bc43945adb39adb0d781df794e639e
1 file changed