target/arm: Add FEAT_NV to max, neoverse-n2, neoverse-v1 CPUs

target/arm: Add FEAT_NV to max, neoverse-n2, neoverse-v1 CPUs

Enable FEAT_NV on the 'max' CPU, and stop filtering it out for the
Neoverse N2 and Neoverse V1 CPUs.  We continue to downgrade FEAT_NV2
support to FEAT_NV for the latter two CPU types.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Miguel Luis <miguel.luis@oracle.com>