Fixed line endings in linker.ld

linker.ld was using the evil dos line endings until now. I've now fixed
them up to the glorious unix line endings. This project is now dos free.
Fixed page table initialisation error

The settings for the page table were being loaded into r6, and then r4
was actually being used to set the page settings. It only before worked
because r4 still contained 0x55555555 from setting up domain permissions.
Improved debugging support in qemu