GPIO7 bug hacking

Concerning this warning

Some people have reported an undocumented bug that can potentially corrupt the I2C bus. It occurs if an MCP230XX input pin state changes during I2C readout. This should be very rare. For more information, see this [forum post](https://www.microchip.com/forums/m646539.aspx) and this [knowledge base article](https://microchipsupport.force.com/s/article/On-MCP23008-MCP23017-SDA-line-change-when-GPIO7-input-change%3E).

It may appear that you can bypass this problematic by using the software interrupt and the interrupt capture register. Doing so you simulate a buffer that avoid the real time change bug which affect the SDA line.

Just a thought by now that I've to test, but first I have to found a solution to replicate the bug efficiently.

No source file or test is named. Start by reading the warning, forum post, and knowledge base article, then determine how to reproduce the MCP230XX GPIO7 change during I2C readout and whether the proposed software-interrupt approach avoids the SDA corruption; done means the behavior is reproducible and a validated fix or documented limitation is established.

Written by the indexing model from the issue text.