core: Introducing an Enum to distinguish archs

This introduces an Enum (called ArchitectureType) to distinguish the
architecture of each supported processor.

Change-Id: I5d63f0c66c2499f76b122d9c5cdbb7eebfe440e8
Signed-off-by: Vitor de Lima <vitor.lima@eldorado.org.br>
Signed-off-by: Gustavo Pedrosa <gustavo.pedrosa@eldorado.org.br>