target-arm: there is no TTBR1 for 32-bit EL2 stage 1 translations

For EL2 stage 1 translations, there is no TTBR1. We were already
handling this for 64-bit EL2; add the code to take the 'no TTBR1'
code path for 64-bit EL2 as well.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1437751263-21913-2-git-send-email-peter.maydell@linaro.org