RVM: Zalrsc should be a valid optional extension #164
Description
RVM lists both A and Zaamo as valid optional extensions.
A = Zaamo + Zalrsc
it only makes sense that since A and Zaamo are optional, that Zalrsc can also be optional on its own.
Zaamo = easy to implement on simple cacheless microcontrollers (and doesn't need Zalrsc)
Zalrsc = might be easier to implement on high-performance multi-core cached microcontrollers (and doesn't need Zaamo)