rdinfra/platforms: rename RD-Edmunds to RD-V2

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

Signed-off-by: Joel Goddard <joel.goddard@arm.com>
Change-Id: I2c0c18265f306511cc6868e31908a3eb59b1c6d4