Remove ARMMEM linker file

Replace all ARM ISRs with the default debug handler.
Embed the memory location of ARM peripherals in Zinc as they are
constant between devices.

Opinions on the naming/location of the getter function in the systick example?
Linker got confused using isr_default_fault as the symbol wasn't being used. These will all be replaced in the future, so this is fine for the time being.