The bulk of the work here, beyond base HPD, is defining the
TTBCR2 register.  In addition we must check TTBCR.T2E, which
is not present (RES0) for AArch64.
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20181203203839.757-11-richard.henderson@linaro.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>