Addresses should consistently use hex values

[rwalle]

https://github.com/babbleberry/rpi4-osdev/blob/c9a2a1429ae7cf0f6d1632c3f4a92fb8457e6c07/part3-helloworld/io.c#L54-L63

The offsets are represented by decimal numbers which are a bit strange, especially as the base address uses hex values. This makes it more difficult to cross reference the data sheet where all offsets are shown in hex numbers. People who follow this tutorial will have to manually convert the numbers back and forth