fix(cpu): correct variant name for default Poseidon CPU

Update the Poseidon CPU variant name to "POSEIDON VNAE" in alignment
with the MIDR 0x410FD830. This adjustment reflects the accurate
designation for the default Poseidon CPU and allows for seamless support
of other variants in the future.

CC: Vijayenthiran Subramaniam <vijayenthiran.subramaniam@arm.com>
Signed-off-by: Rohit Mathew <Rohit.Mathew@arm.com>
Change-Id: I48183290ffc2889d6ae000d3aa423c0ee5e4d211
2 files changed