refactor(sgi): rename RD-Edmunds to RD-V2

Neoverse Reference Design platform RD-Edmunds has been renamed to RD-V2
and so all corresponding references have been changed.

Signed-off-by: Joel Goddard <joel.goddard@arm.com>
Change-Id: I134f125f8ce9ec2f42988ecd742de307da936f2b