Fixed EPD_4in2b_V2 not working on raspberry pi b+ v1.2

[shultays]

I am not sure how this fixes it but on raspberry pi b+ v1.2 EPD_4in2b_V2 c version wasn't working for me while python version does. I started comparing the code and noticed that python has 5ms delay here and when I changed C version to 5ms as well it started working

In C version drawing/clearing was all glitchy. For example clear function was just trying to clear part of the screen I think