refactor(cpu): use the updated IP name for Demeter CPU

Neoverse Demeter CPU has been renamed to Neoverse V2 CPU.
Correspondingly, update the CPU library, file names and other
references to use the updated IP name.

Signed-off-by: Joel Goddard <joel.goddard@arm.com>
Change-Id: Ia4bf45bf47807c06f4c966861230faea420d088f
7 files changed