integer_overflow_sizeof: add a check for integer overflows involving sizeof()

integer_overflow_sizeof: add a check for integer overflows involving sizeof()

The problem with integer overflows is that they are often harmless so there
are a lot of false positives.  By targeting math which involves sizeof()
then the hope is that this will be warn about high value overflows.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>