target/arm: Treat LDTR* and STTR* as LDR/STR when NV, NV1 is 1, 1

target/arm: Treat LDTR* and STTR* as LDR/STR when NV, NV1 is 1, 1

FEAT_NV requires (per I_JKLJK) that when HCR_EL2.{NV,NV1} is {1,1} the
unprivileged-access instructions LDTR, STTR etc behave as normal
loads and stores. Implement the check that handles this.

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>